if we talk about the next 5 years. I don't think it's 99%, but all crypto including bitcoin. the reason is when bitcoin has reached the total supply, people will think crypto is no longer profitable.
It will be wrong to believe the words of each guy, even if he is a respected and famous person. As we remember, 99% of these prognoses fail, and it is not a fact that almost all altcoins will be forgotten in 5 years or even earlier. There are tokens, which will be working as great as Bitcoin, and maybe, be even more popular with users. I mean Ethereum here, and even NEO, which is going to be upgraded.