I in many ways can see BTC as but the first evolution in something greater to come. The simple fact of the matter is that it is not 100 percent sustainable. A better technology will have to come out that is both faster and consumes less energy. Perhaps BTC in whatever from it become dominant (Cash, Gold, 2x) should relegate itself to a store of value and relinquish the idea of becoming an accepted everyday payment medium. Bitcoin has brand recognition right now which will only get you so far once other aspects of the commodity begin to fail; costs, speed, reliability, stability etc.