...not a guaranteed value of the Bitcoin makes the price move is not fair.
Life is not fair. The fact that bitcoin is not guaranteed by state violence is the very reason it will succeed, the very thing that makes it unique from all violence-backed state promissory scrip.
No, bitcoin will not last forever. But it will almost certainly get us through the end of capitalism.
I think the future Bitcoin will flourish. Because it is a progressive currency, a currency breakout. Some people do not believe in Bitcoin's sustainability because it's so alien and different. But for those who have used Bitcoin, they fully trust Bitcoin's beautiful future and their participation in Bitcoin.