This author isn't fundamentally confusing two entirely different points.
The first is the idea that, as a marketplace for goods, there are a lot of--maybe (if you go all in on the premise) even the majority of--sales to be made within the long tail. Maybe you believe the 80/20 split the author here posits is a good reason to discard the 20%... I think that's dumb and I think that both Amazon and Spotify are constantly cited somehow in this article as doing something wrong demonstrates as much.
But... the article spends most of its time moralizing about a very very different idea: a frustrating claim that anyone who believes in the long tail ever promised that if someone allocates their effort to making a product for a niche audience that they will make a bunch of money because "the blockbuster is in decline" not merely in total sales volume (due to the relatively new accessibility of the long tail) but is somehow a worse bet than making a niche product for a small audience.
That is not only not the case in practice it is actually trivially not the case from the very idea of the long tail: every product on the long tail isn't making many sales by definition of where they are in the distribution. At one point this author finally states as much... but somehow it is against the long tail people, as this idea that people should go out of their way to make content for this segment was attributed to them as the most disingenuous form of strawman throughout the rest of the article :/.
The long tail argument is merely that if you sell a bunch of stuff that a non-negligible amount of your sales comes from the long tail, not that the long tail is somehow itself fat and that the people making those products are going to ever manage to pull off a bunch of sales. If it is wrong, it is because people might want it to be a majority and not just "a lot", but FWIW in my experience 20% is "worth it", and if I went to a supermarket that only stocked the 10 most popular foods I'd find a better supermarket even if 80% of my purchases and 80% of their sales are from those 10 foods: it is really hard to run a business that only serves blockbusters.
But... is it sane to allocate a bunch of time and money to making something that isn't a blockbuster if your goal is to maximize profit? Of course not, and no long tail advocate ever claimed as much! If you're concerned about where all that content comes from--and I can tell you this as someone who ran a very popular and even culturally-relevant content marketplace--it is largely people working on low or even negative budgets and for whom even a single sale is a life-altering moment.
But like, if you take a percent of that person's one sale and you add it to the numerous other peoples' one sales, does it add up to "a lot" of money? Without even having to chime in with my own experience, we can actually note that even this author seems to claim--by their assertion in 80/20 or (later) 75/25--you could increase your revenue by 25-33% by bothering to open up your catalog... and that's even more the "I don't bother to shop at a supermarket where I can only find 90% of what I want"!
The author thereby needs to stretch pretty far to explain away why markets like Spotify and Amazon disagree with the article, claiming that Spotify is I guess just wrong and will likely change their strategy in the future once they realize this author is smarter than them and that Amazon makes most of their money on AWS and so (supposedly) isn't a relevant data point... maybe it would surprise the author, then, to learn that Apple iTunes also allows pretty much everyone to list their tracks (and thereby contains an extremely long tail that certainly doesn't make people a lot of money but which absolutely helps cement them as a go-to destination to buy and collect music) and that, while Walmart has to make some tough decisions on shelf space, they have an extremely expansive online-only catalog.
The only example they have of a marketplace (as the idea that a movie producer concentrates on blockbusters is not relevant to the premise) shrinking their content catalog is Netflix, and that's not at all Netflix's conscious strategic decision: they only were able to have all of that content for so long because the people who owned it didn't want to directly compete with Netflix and were willing to license it "on the cheap"... now that they all want their own streaming service, they are clawing back their interests region by region, and it frankly isn't clear that the gutted separate services are going to manage to sustain their users as well as the unified market could (which I will claim is in no small part due to long tail effects; their best strategy will likely be to re-form the old cable market by joining forces under a single subscription).
I'm honestly not sure why this article has managed to captivate so many people given how mixed up it is in the premise, but I hope that readers spend some time really thinking about not only whether the points made in this article resonate in the order presented but whether they manage to correctly lead to the moral and economic conclusions they purport to before anyone ascribes to "the long tail" something only this author incorrectly understood and start--as I have seen many do--using it to justify actively shrinking a catalog or the idea that a large catalog isn't somehow a powerful moat (which someone tried to use against me once to claim how easy they thought it would be for just anyone to compete with Spotify).
The first is the idea that, as a marketplace for goods, there are a lot of--maybe (if you go all in on the premise) even the majority of--sales to be made within the long tail. Maybe you believe the 80/20 split the author here posits is a good reason to discard the 20%... I think that's dumb and I think that both Amazon and Spotify are constantly cited somehow in this article as doing something wrong demonstrates as much.
But... the article spends most of its time moralizing about a very very different idea: a frustrating claim that anyone who believes in the long tail ever promised that if someone allocates their effort to making a product for a niche audience that they will make a bunch of money because "the blockbuster is in decline" not merely in total sales volume (due to the relatively new accessibility of the long tail) but is somehow a worse bet than making a niche product for a small audience.
That is not only not the case in practice it is actually trivially not the case from the very idea of the long tail: every product on the long tail isn't making many sales by definition of where they are in the distribution. At one point this author finally states as much... but somehow it is against the long tail people, as this idea that people should go out of their way to make content for this segment was attributed to them as the most disingenuous form of strawman throughout the rest of the article :/.
The long tail argument is merely that if you sell a bunch of stuff that a non-negligible amount of your sales comes from the long tail, not that the long tail is somehow itself fat and that the people making those products are going to ever manage to pull off a bunch of sales. If it is wrong, it is because people might want it to be a majority and not just "a lot", but FWIW in my experience 20% is "worth it", and if I went to a supermarket that only stocked the 10 most popular foods I'd find a better supermarket even if 80% of my purchases and 80% of their sales are from those 10 foods: it is really hard to run a business that only serves blockbusters.
But... is it sane to allocate a bunch of time and money to making something that isn't a blockbuster if your goal is to maximize profit? Of course not, and no long tail advocate ever claimed as much! If you're concerned about where all that content comes from--and I can tell you this as someone who ran a very popular and even culturally-relevant content marketplace--it is largely people working on low or even negative budgets and for whom even a single sale is a life-altering moment.
But like, if you take a percent of that person's one sale and you add it to the numerous other peoples' one sales, does it add up to "a lot" of money? Without even having to chime in with my own experience, we can actually note that even this author seems to claim--by their assertion in 80/20 or (later) 75/25--you could increase your revenue by 25-33% by bothering to open up your catalog... and that's even more the "I don't bother to shop at a supermarket where I can only find 90% of what I want"!
The author thereby needs to stretch pretty far to explain away why markets like Spotify and Amazon disagree with the article, claiming that Spotify is I guess just wrong and will likely change their strategy in the future once they realize this author is smarter than them and that Amazon makes most of their money on AWS and so (supposedly) isn't a relevant data point... maybe it would surprise the author, then, to learn that Apple iTunes also allows pretty much everyone to list their tracks (and thereby contains an extremely long tail that certainly doesn't make people a lot of money but which absolutely helps cement them as a go-to destination to buy and collect music) and that, while Walmart has to make some tough decisions on shelf space, they have an extremely expansive online-only catalog.
The only example they have of a marketplace (as the idea that a movie producer concentrates on blockbusters is not relevant to the premise) shrinking their content catalog is Netflix, and that's not at all Netflix's conscious strategic decision: they only were able to have all of that content for so long because the people who owned it didn't want to directly compete with Netflix and were willing to license it "on the cheap"... now that they all want their own streaming service, they are clawing back their interests region by region, and it frankly isn't clear that the gutted separate services are going to manage to sustain their users as well as the unified market could (which I will claim is in no small part due to long tail effects; their best strategy will likely be to re-form the old cable market by joining forces under a single subscription).
I'm honestly not sure why this article has managed to captivate so many people given how mixed up it is in the premise, but I hope that readers spend some time really thinking about not only whether the points made in this article resonate in the order presented but whether they manage to correctly lead to the moral and economic conclusions they purport to before anyone ascribes to "the long tail" something only this author incorrectly understood and start--as I have seen many do--using it to justify actively shrinking a catalog or the idea that a large catalog isn't somehow a powerful moat (which someone tried to use against me once to claim how easy they thought it would be for just anyone to compete with Spotify).