The PC app ecosystem is a tiny fraction of the App Store's, outside of, notably, Steam's locked down closed ecosystem.
Having a single way to pay, subscribe, cancel, browse apps, beta test versions, and update apps, proved to be a huge game changer for making software accessible while also minting millionaires around the world in terms of small development teams.
In 2024, computer software generated around $373b in revenue while mobile apps generated around $522b. Given that smartphone usage is significantly higher worldwide than computer usage (around 2 to 1 ratio), the stats do not really support your thesis that locking down software access to the whims of a monopoly hegemon results in a massive financial boon to application developers. Even if it did, it still would not justify the harm to the end user entailed, but it also just doesn't do what you say it does to begin with.
Incidentally, while looking this up, I discovered that 2/3rds of that $522b in app revenue comes from in-app advertisements. And here somebody was trying to mock Windows for being adware friendly circa 2005. Good lord.