The problem is what they will do when they are at the top (or hitting rock bottom). Or when their stakeholders want to milk the cow.

It's similar to how you don't want companies to have your personal data, even if you trust them "100%". When money becomes a problem, or a solution, you'll be their last priority.

Some of the news about Windows 10 would be unthinkable a few years ago. Priorities change, and this company in particular has a history of being extremely hostile.