Pretty much everything in there still works, if I type it in and compile it with the current Visual C/C++ toolchain. I might need to get rid of a few MOVEABLE and DISCARDABLE tags here and there, I suppose.
Idk, and I'm not saying it's not a good question, but it's irrelevant to the comparison in OP's comment.
which on one hand, good -- fuck microsoft and the monolith; on the other hand we get react start menus when we have to use microsoft.
What's the issue?
Other apps are successful despite being slow and bloated, since performance isn’t a primary concern of users. In contrast it’s critical for OS internals like the start menu, so a javascript runtime and framework is just the wrong tool for the job.
React only makes sense as a layer on top of the browser DOM, because the DOM itself cannot be fixed without rewriting it from scratch, so making it usable for non-trivial UI needs to happen in the 'framework layer'.
But without the DOM as the thing that needs fixing and the restrictions of the single-threaded browser-event-loop, the React programming model simply doesn't make a lot of sense. Using the "React-paradigm" outside the browser (e.g. SwiftUI, React Native) is pure cargo-culting, it only makes sense for onboarding web-devs who are already familar with React - but makes it harder to create UIs for anybody else.
The actual problem in the context of Win11 is of course that Microsoft doesn't have any sort of longterm strategy for Windows system APIs (not just UI frameworks). The only long-term-stable API is Win32.