Governments are santioned by 'we the people' with the use of deadly force to enforce rules that 'we the people' agreed on. I don't see how the blockchain can pick up a gun and coerce them into action. That part of the government is needed. If the democratic government doesn't do it, then you have anarchy (anyone with a gun) then dictatorship (one guy with a gun).

In a land where anyone with a gun wins, I would lose, as I am not a big tough guy. I like civilization.

Having said all that I think blockchains can remove much of what government does for us. Especially the record keeping part.