I see, we're dealing with a serious lack of foresight here.
Gvt of the world will not willingly convert to BTC. They will do it because their economy will eventually crumble and BTC will be the only safe asset left.
Here, some reading for you:
http://nakamotoinstitute.org/mempool/speculative-attack/
1. A government does not have to willing convert to BTC with their fiat system. Add a law bada bing bada boom, and they tax your Bitcoins.
And the guys who run the nakamoto institute are a bunch of young kids who have not experienced real life yet.