No one will come to guarantee that there is certain altcoin that will make you millionaire 5 years from now. For me, that is quite a short term, but maybe possible 10 or 20 years from now. But IMHO, everything in crypto is still uncertain, even bitcoin itself. Of course, all projects are formed from the image of successful coins, but not all of them are bound to succeed. So invest but not expect, but rather take the risk and manage to lessen the risk. That way, you will have higher probability to succeed.
Yes you can’t guarantee such. You can just be trying your luck if you have the money to spare for such thing. There are people I know that likes investing in any new coin they see and they think that it is good and would be profitable in the future. They are not certain about it, they are just investing and hoping that the coins are going to be successful in the future and would make them profit.
But, if he has like $500,000 (five hundred thousand dollars) and he invests it in Bitcoin, I think he might possibly make like $1 million in few years. If bitcoins halves, I feel that the price would double. We are currently at 40k, so if we should hit $100k as analysts are predicting , then it’s double and a plus for him.