States can legalize the circulation of bitcoin. It is very important that there are acceptable conditions for its circulation and an infrastructure is created for its use as a means of payment. But at the same time, they will try to tighten both the conditions for his walking and tax collections. It is also not yet clear how a possible ban on mining cryptocurrencies with an energy-intensive PoW algorithm, which is likely to be introduced by states, will affect bitcoin.
The number of cryptocurrency users will certainly grow and one billion is just the beginning. But cryptocurrency is not just bitcoin. Altcoins are now showing better results, and this, apparently, Bitcoin will have to put up with.