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.
That is why we always need to research about what we want to invest, so we don't make a wrong decision. Only the weak altcoin that will disappear from the market, and that will no need longer to see that. I think from the last 2 years ago, and the market makes a selection for the altcoin so only the strong altcoin that will still exist on the market.
In the future, we will have more altcoin that will release, and the market will make another selection, and bitcoin will adjust the price to a new rate. But at that time, bitcoin price will still at the top position on the market.