This review is kinda misjudged. Like a Master of Wine reviewing a bottle of moonshine: dude this wasn’t made for you! Writing does seem a little like a start-up these days: write, assess the market response, adjust accordingly. This writer has done just that, including a freemium tier, with no cost books, and has shifted 20k units. Highbrow it’s not, but that’s a different market with very different gatekeepers.
You have Oppenheimer and you have Barbie. They are both "movies" technically but are completely different type of products that happen to use the same media for dissemination. Her books are no different; I like your start-up analogy because she's focused on making money through this particular media and not "writing books" in the same way, let's say, Gabriel Garcia Marquez wrote books.