Hi @superfluousman!
Your last sentence is the key. You wrote, "As long a demand exists there will be a market..."
True. That is precisely why governments will probably not "ban" cryptocurrencies. This would just turn them into a black market. On the other hand, if they can kill the "demand" then they will simultaneously kill their enemy. Killing demand is super easy: poison the well. If central banks turn their AI bots on Bitcoin with the goal of NOT making money (i.e. actively LOSING MONEY and crashing the price) then it is all over. Yes, the central bank in question will lose a few billion of their fraudulent fiat dollars in the process, but so what? They can always print more. In the process of hitting the Bitcoin market with a well-orchestrated barrage of sell orders over a period of time, all but the foolhardy would start to avoid the cryptocurrencies like the plague. Nobody likes getting a good solid kick in the nuts every day.
RE: Why Cryptocurrencies will fail… eventually.