While this piece is definitely insightful and worth taking seriously, I would argue that the issues presented here are a bit of a simplification. I think there is a mistaken mindset that self-publishing authors shouldn't NEED to invest money in their business...or worse, this idea that authoring books isn't a business at all.
The fact is that it IS a business, or at least an entrepreneurial career, and it takes investment of time, money, and experience to succeed. That includes spending a large portion of time marketing your books and not relying on algorithms to do all the heavy lifting for you. I wouldn't call our industry competitive, because demand is only increasing for self-pubbed books and it's not as if people just read one and that's it. But there ARE a lot of clamoring voices and it's inevitable that during times like this we'll need to market more to get heard.
I also think that many authors put waaaay too much stock in "letting amazon do the marketing for you" by relying on matching and preferences. We SHOULD be using Medium, social media, email lists, etc etc to succeed - because these are all ways to engage with readers. Sometimes it costs money to market, but mostly it's a cost measured in time and the ability to utilize many different tools at once until a strategy emerges. Amazon makes money when people buy books, full stop, and their model continues to thrive on simply putting the content most likely to = a purchase in front of people. Ads aren't really a part of that and I'd argue that they are a totally different part of the Amazon business model altogether.
It's just that there are a lot of books, a lot of readers, and it now takes a very skilled and nuanced approach to see significant results in bringing your books and "your" readers together. But that's not necessarily a bad thing if you're willing to do the time and learn.