Why would they allow Bitcoin to continue like this and grow momentum? All they would have to do is outlaw it and 90% of the world population would bitch out immediately and stop. But they don't do it.
central banks aren't a united front. you have to consider geopolitics, and the fact that nation-states are competing against one another.
if one superpower prohibits BTC, they might put their industry and population at great disadvantage to the rest of the world. this is a nascent industry where there is potentially massive economic growth and transfer of wealth. it would be outright foolish to purposely get left behind.
if all the superpowers and most of the others all agreed to ban BTC, maybe you'd be onto something. but that would never happen!
Indeed, It wouldn't happen mate and with bitcoin's decentralized character government could not prevent every people to use bitcoin for their private purposes. In fact there were selected countries in asia right now adopted bitcoin as a form of payment. That's why we seen bitcoin continued to reach higher in terms of profitable appreciations from an optimistic person who has a wide thinking. Central banks couldn't stop this to transact towards money transfers, because it's considered as business matters and as long as the system was having transparency towards their clients then the banks has no issues raise particular on possible fraudsters.