Well Japan has done it, so we know for a fact that it's certainly possible. It's true that it could make a huge mess though, and it does seem like Japan is an outlier in this issue.

But hey, if Bitcoin reaches global adoption, and the people decide they only want to spend in Bitcoin, I don't think governments will have much of a choice. Either they give in to pressure, or businesses, and in turn the economy, suffers. I know I'm speculating and that this is something that could only happen way into the future, but it's possible.