If the price doesnt rise then the miners stop mining because of lack of profit, Once this happens the network becomes less secure and bitcoin starts dying off. Whats to stop this from happening? Maybe we are getting to prices that cant be maintained with the current user base. I wasnt here at the last halfing and the price will need to be much higher so im not too sure what will happen.
I think that answer is pretty simple, bitcoin would die, as all bitcoins miners wouldn't get any profit so they would leave their jobs
And with no miners bitcoin would die pretty soon, unless there will be new miners that have very cheap electricity and they still will get profit