OpenSolaris came after regular Solaris. It was a retroactive opening of code, and wasn't as essential to regular Solaris. In contrast, Fedora is quite instrumental to RHEL's existence. CentOS is not that instrumental, but it's not a major cost sink either. It used to be community driven earlier and can become so again. i.e., Unless they go out of their way to do something malicious, which would have little payoff anyway.