I believe the reason why investors continue to invest in crypto is that the high potential to earn and gain huge profit is here. Crypto currency is profitable, Investors take the risk of all times that's why they become richer and richer.
As an investment, no investment instrument can give gain like bitcoin. Bitcoin give 1000% gain in 2017 and even the price drop to $6500, bitcoin still profitable if investor buying at early 2017 because early 2017 bitcoin price only below $1000