I think that 95% of crypto coins and tokens won't survive and the reason is that a crypto coin in order to survive and get value it has to be accepted as a way of payment for purchase goods or services.
Very few coins will manage to do it at the end of the day and of course these coins will get enormous value.
The only thing you have to do is to find out which coins will enter the market of real currencies.
I think you are right about that. Most ICO's disappear once the market drops and turns out to be a scam ICO. This projects are the reason why less people trust the process of Initial Coin Offerings (ICO) because most of them tried to invest before but failed to generate profit or worst is lost money.