Different people have different attacker models. I can imagine something like this would be perfect for keeping a mostly airgapped machine to access archives of documents created by Windows. (Or to use legitimately licensed, pre-everything as a service software in perpetuity)

In any case, if you wanted security in the way you describe, how would you justify running Windows 10 at all? The onus isn’t on this project to secure Windows when they had no part in making it insecure to begin with. If Windows were open source, these measures wouldn’t be necessary, and wouldn’t result in less security. This is the current best effort that the devs can do to accomplish their goals. It’s fair to criticize the goal or the results, but issues you’re describing are present in stock Windows 10 to begin with.

I’m sure that some kind of auto build script could be created, so that whenever new Windows Updates are released, a new build is created.