I don't know for certain but I have a theory - I believe some programmes collect and use bits and pieces of the Windows operating system rather than being a standalone completely self-contained programme.

I think over time and a number of restarts Windows manages to claw back some of those bits and pieces but not all. This effectively stops the programme working properly or altogether and when it is finally uninstalled the remaining bits and pieces of Windows disappear also so when it is reinstalled some essentials are absent...

Windows can function fairly well with lots of bits and pieces missing.

It is just a theory you understand, based on my experiences and observations.