I think that bitcoin and cryptocurrencies idea will last forever, but they gonna be verified by market/people.
Alot of projects will die, but Bitcoin and Ethereum will stay with us. Why Ethereum too ? Because there's alot of smart contracts made on this.
Crypto currency trend is a new emerging trend and I think that it will continue for a long time and not going to end so soon. Although some cryto currencies will come to an end but they may be scam altcoin or may be come to an end for some other reason, but it does not mean that cryto currencies are going to end totally. I think beside Bitcoin and Etherium there are so many other altcoins which will continue survive for a long long time.