Stop dreaming. Won't happen. Windows is a purely additive effort. WSL is what happened, and when it couldn't do some things they built WSL2. As another comment

Stop dreaming. Won't happen. Windows is a purely additive effort. WSL is what happened, and when it couldn't do some things they built WSL2. As another commenter pointed out regarding the integration of this new "sudo" and UAC prompts, it will probably be done in a new, separate, different tool, because this new, freshly released "sudo" will now have to remain bug-for-bug compatible for the next four decades.