Its either you don't understand the whole idea of blockchain and cryptocurrency or you are just ignorant of the true purpose of blockchain and cryptocurrency. There is no way cryptocurrency will disappear. Cryptocurrency is the new revolution of money and its gradually changing and transforming the way people do transactions online.
Totally agree with your opinion. Cryptocurrency market is the future and to me, this is only the beginning of the virtual money. But definitely cryptocurrency ewon't disappear, it will be developing more and more