That's the beauty of proof of work, it makes more sense to compete mining than it does to war against the blockchain itself. And the more competitive mining is, the stronger Bitcoin becomes from the cumulative proof of work.
Central banks are missing out every single day that passes on the opportunity to become a significant part of a more powerful system than theirs, and every day they hold off, Bitcoin accumulates just a little more work on it's blockchain and becomes that little bit stronger. Conversely, every day that unpayable sovereign bonds become that little more unpayable, the central banking system gets slightly weaker.