Am I understanding your concern?
I don’t see how microsoft giving back has anything to do with Blender degrading in quality since the foundation is a place to donate.
I don’t see it like I do the stock market and investors changing the goals of companies.
I think it is great news that microsoft is joining. It means bigger companies are taking blender much more seriously in their workflow. It may even mean my engineering company will accept it as a program in their It workspace one day and stop wasting money on software that does the same thing.