The trick here is that people may not want to be coding MinIO. It's like... just not that fun of a thing to work on, compared to something more visible, more elevator-pitchy, more sexy. You spend all your spare time donating your labour to a project that... serves files? I the lowly devops bow before you and thank you for your beautiful contribution, but I the person meeting you at a party wonder why you do this in particular with your spare time instead of, well, so many other things.
I've never understood it, but then, that's why I'm not a famous open-source dev, right?