Regarding the future of Bitcoin and its Tragedy of the Commons economic design:
At best one would see the type of cartel that TPTB_need_war has suggested; however my take is that this kind of cartel would only last for a short time before collapsing. Just witness what is currently happening in the crude oil market.
Cartels form in power vacuums. They must align with the greater power vacuums in order to sustain their market inefficiency (top-down control can't anneal maximum fitness). So the only way such a cartel would not fail, would be to become a fiat of the world government and be sustained by the
Iron Law on Political Economics which is the perennial, inimitable power vacuum.