Already started there is no bright spot that will arise in an ICO so it's time to go and find other ways to make coins that can make you a millionaire.
Good luck becoming a millionaire in crypto now. It was possible back in 2009-10 and maybe even up to 2015 if you had enough investment capital and had the foresight to hold bitcoin through 2017, but now everyone knows about bitcoin and I seriously doubt there's going to be growth like there was in the early days.
It is never going to be as easy as it was back then but someone that had a decent capital could still become a millionaire with cryptocurrencies, but if you are only using the top coins then I estimate you will need at least 100000 dollars and decent skills as a trader.
Even if bitcoin only produced 5x during the next decade a talented trader should be able to get at least twice that amount, is it possible to get 10x during the next decade? I believe so but few will have the patience to pull it off.