Impossible bitcoin could be over because many investor keep trust with bitcoin, keep holding and waiting with bitcoin growing up to higher price, maybe bitcoin could be over when all country have banned bitcoin.
Banning bitcoin in most of the country is never impossible. It can surely happen if bitcoin will destroy the economic state of one's country. For example, the bitcoin will cause a great war if it is in demand and in a very limited number. If the bitcoin source is over, they will fight for the money because for sure bitcoin will make a higher price if it is limited. So it is possible for the bitcoin to collapse.