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!
Yes I will keep using bitcoin in fact having a stable price will be great since I will not have to worry to leave my coins in my wallet for a long time and that the price tanks or something so it will be one less thing to worry about, and that will probably incentive business to accept bitcoin and keep the bitcoin instead of selling it right away.