I'm on dev release channel (in order to use WSLg, very nice so far), and it has an updated look&feel in Explorer.

But Settings / Control Panel needs to be reversed. Just got a new computer, and having to look both places to find a knob is annoying. Settings is also too dumbed down and spacey to be usable. And actually slow to navigate.

But don't think they should or can break compatability as you suggest. Firstly, not having shit break every update is one reason I moved off MacOS and back to Win. But also for MS's part that if thing breaks and they have to do big upgrades, users might as well look elsewhere. People keep using Win because it works for them and the incentive to switch vs cost is low.