I don't think that the governments would ever support bitcoin, as they want to completely control the economy. At best , they can do is to float their own cryptocurrency so that they can control it in some way or other.
There's nothing to lose for them if they will start supporting it like to say that it's good to use as an alternative payment. If a gov't doesn't want to support bitcoin then we won't see any country that will allow it on their jurisdictions.
They may not give same national credit with fiat but as long as they are supporting it in a way that they allow it, I think that's already a good indication.