I don't think cryptocurrencies will disappear. Cryptocurrencies allow you to make very cheap and fast payments between users. This is a real benefit that is in demand. Bitcoin and major cryptocurrencies will not disappear
For me cryptocurrency will not be disappear because as of now many cryptos are really trusted by many people and there are so many good benefits we are getting on cryptocurrency, that's why i am confident that crypto will be more popular in the future.
aside from the benefits that crypto gave to us there are also known disadvantage with it and this was the reason why people loose and gave up easily but thankfully the number of crypto users vs to non crypto users are still bigger so there is a big possibility that cryptos wont end or dissapear completely . those who are going to die are the ones that arent usefull enough ( sh8t tokens for example ) though they are being replaced easily by another sh8t token .