No one can really predict the future of any investment. But as for the future of cryptocurrency it cannot die but because many people are into the business now it can only be fluctuating that is rising and falling.
personally I agree with your opinion, it is true that the future of crypto itself is very difficult to predict and we can all speculate about crypto as an analysis for future investment. I think as long as the internet in this world continues to exist and there are still many people who believe in crypto forever will never die or disappear from circulation.
Basically, any investment will always fluctuate, including Crypto itself, because there are trading activities that cause it to happen and make the price go up and down depending on the market capitalization situation.