Bitcoin isn't their Plan B. They would never introduce something they can't control.
Marxism, Communism, and Socialism have failed repeatedly, and have always hurt the poor and lowered the quality of life for everyone. But despite repeated failures, they still succeed in spreading the same failed ideas on the internet.
This, the current Government systems love their Fiats it makes all the ones who they want rich and can control what they do with it, hell there's a reason there is no gold standard fiat anymore.