...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.
Bitcoin mining is how new bitcoins are brought into circulation but the future of bitcoin after they are all mined is still unknown.