The C89 issue is completely unrelated.
If you want to hold on to C, there is clang and GCC.
There are multiple occurrences of this statements from Microsoft employees blogs and talks, apparently some keep missing it.
And actually VC++ compatibility with ISO C has been updated to the extent required by ISO C++, meaning C11 standard library, and some language constructs that were considered relevant by major customers.
The people in question are not missing it. I'm not missing it. The only thing that needs to happen is a decision in the CPython project is to drop MSVC support, move to C++, or give up on C99 and C11.
But it will have taken a long time to get there are they've wasted that time in the meantime waiting for the penny to drop. My point is that is the release channel through the Microsoft Store is held up like the C99 support that never came, then it will be an inconvenient situation for many Python application developers.
But I guess we all use nix, guix, or venv to distribute things so it's no bother at all. (I don't even use Windows on any machine so I have absolutely no skin in the game here).
Plus some C11 language constructs considered relevant enough to support as C++ extensions, due to customers or high profile FOSS projects.
No idea who are "we all use nix, guix, or venv".