Nah. They can stop it any time they want to. But they won’t stop it until they have to … when and if it ever begins to truly complete with government controlled currencies in the real economy and banking system. At that point they can mega-tax transactions, shut exchanges, etc. But crypto currencies are still a blip in the real economy so they don’t need to do anything and rile up the crazies.
They’re true value is in money laundering. But FinCen is already all over it … bitcoins were being converted into gift cards, now those transactions are reportable to the government. For now speculators are just sucking up the other side of that money laundering trade with nowhere else to spend them in size, but that will end eventually too. Plus bitcoin seems to be pretty bad at anonymity after all!!
So I wish you all luck taking money from each other. But nobody should brag about bitcoin gains unless they’ve already converted back to an actual currency!