Most open source projects taking that path have eventually been forked when someone created new assets under a free (as in beer) license and changed the name. The original project is now nothing while the fork is big.

RHEL continues not because of assets but because Red Hat has people who staff who know the ins and outs of RHEL and will fix it. Red Hat employs many kernel developers because when a customer has a problem the customer knows an expert will get on the problem right away. The guy they talk to on the phone is useful, and can solve the vast majority of problems (as could any well trained system admin), but when you get to those rare special cases Red Hat is better able to handle them quick.