John Gruber has a theory about why Apple will never completely eliminate macOS and go iPad-only: "The Mac being heavy allows iOS to be light". That is, iOS can be free of a bunch all the cruft that comes with the long history of desktop operating systems because the Mac has that for the people who need those scenarios.

I think there's a similar dynamic at work here: full Visual Studio has a lot of powerful capabilities that are only used by 1% of its userbase, but each person needs a different 1%, and much of it is legacy Windows stuff. VS will continue to bear the burden of having all that so that VSCode can continue to be reasonably lightweight and updated quickly.