it is a new world and there is no way for those "in power" to stop it.
oh, yes, there is way
http://project.ukrinform.ua/news/virtual_currency_bitcoin_banned_in_ukraine__73534/but even in the case that there would not be way, is very possible for them to make it the option of the poor people and take the big resources and purchasing power for them with other coexisting currencies backed by governments, laws, oil, gas, gold...
i think cryptos do not just need to grow themselves but also get rid of the central planned enemy, maybe by force. However, I see an intermediate way: fight for gold backed national currencies. This is the only way to keep purchasing power of cryptos, IMHO
In 1944, in the Bretton Woods Accords, Americans (USA) did a very good thing for liberty. They backed their national currency in gold, the same that the reserve currency. Unfortunately this setup was broken by Nixon 27 years after. You cannot allow governments decoupling their currency from people's currency since you would be back to a neo-feudalism.
No they cannot stop the tech.. u didnt get it. Sure u can choose what tokens u want ppl to pay taxes off with but u cant stop all forms of exchange between the tokens.