It's just the nature of the world of computing these days. Mobile app stores are humongous today. Win32 forever and always just doesn't seem to fit today's mold. I get that people here say their PC isn't a smartphone. Is that really how most see it these days?
Complete nonsense. You know who wants these walled garden app stores? The companies that run them. No one actually asked for them, and they offer no real benefits to anyone except those companies. Plus, app stores are hardly some sort of guarantee of quality on any platform, quite the opposite in most cases.
Don't confuse them being ubiquitous with being beneficial to users. There's zero reason your Netflix/Hulu/Uber app needs to exist within a closed store framework.
It's not "the nature of the world of computing these days", it's the nature of corporate tech marketing and it's being sold to you only because it benefits the likes of Apple and Microsoft.
It's good that Microsoft shit the bed with this. They paid Remedy to make this a UWP game in the hopes that it would drive customers to the app store and dispel the criticism their platform has been receiving, and it has done exactly the opposite.