If there is no demand then the price will go to 0$ but as mentioned above, that's unrealistic and impossible to happen.
I agree that, if there is no demand the price of bitcoin will become $0 and I think it will vanished. In addition to that, I hope people will contiue on buying bitcoin because it may result to high demand and high price. Lastly, I think bitcoin will die if no one buy or no one use it and I hope it would not happen.