Many people think that Bitcoin is like a bubble, so its price goes up rapidly to its peak and will plummet.
Bitcoin have bubbles, they comes and goes periodically. Altought behind that you have real revolutionary technology.
So it doesnt matter if there is bubble sometimes, bitcoin itself is revolution and there will be always price on that, what price? it depends, but i doubt it will fall in price in next 20 years (in big period of time of course)