Objectively, bitcoin failed. Users and holders must trust that those top 5 miners will not do anything nasty. If they conspired to put all other miners out of business, they could do it. If they agreed to block an account forever, they could do it. If they agreed to make some change to the protocol, they could easily force everybody do accept it. There would be much cursing ang grawing of teeth, but the only choices for all users and holders would be to either accept the change, of lose their coins. Since the whole point of bitcoin was to eliminate the need to trust an intermediary, the system has become pointless.
You know what? I think they should - before some government does when we can't do anything about it. At least for a 48hr period to demonstrate the consequences and it is a real threat that needs to be addressed. Lock the main devs bitcoin addresses for a couple of days to focus their attention; first on the testnet then on the real net. Put out a public warning a week before and goad the devs to stop them if they can. Treat it as a white-hat DOS test with full disclosure.