But the problem is the user interface and programming environment is shit for anything past basic stabby finger novelty apps and no one trusts them enough to invest heavily in it. Oh and the store is a desert of turdblossoms.
Well, kind of. The issue is that Centennial also mostly overrides UWP's sandboxing. (Notice Centennial apps have "full access permission".) This is not a good solution, it is a stop gap.
UWP is more than capable of supporting advanced, quality desktop apps. The issue is just that while Windows 7 is so prevalent, developers have little reason to prioritize native UWP dev, which won't run on half the Windows userbase.