I think most users are involved in Bitcoin not because they belief in the technology, but because they hope the price will go thru the roof. So let us say the price would be at $900 for the next 50 years.
Would you still use and buy Bitcoin or would you leave?
EDIT: Poll added!
Of course even $500 will do . It is true that bitcoins price fluctuation plays a great role and it is the thing that attracts most people to it . But even without that I think that bitcoin can stand alone . You can still save a lot if you use bitcoin since it has low fees and whats more if it will be accepted by most merchants? . And what I like about bitcoin besides its fluctuation is the authority to control my own money, I can be my own bank and if the price is stable it can be considered as an asset cause there willl be no risk that your money in bitcoin might go $0 .