How many people are joining? How many people are joining because or in lieu of Linus? How many people are joining just because it’s Linux/Git/whatever (although granted that is in part due to Linus making them such big things)? How many people would have joined/wouldn’t have left if he wasn’t there?
People don't have a universal right to collaborate to this project, especially on their own terms.
In the same way, these projects will like you said, evolve in positive or negative ways with no God given right to exist and thrive.