Read again what I said. The kid invested $1000 and was successful years later. If the kid were an adult and had no job, he would have sold his BTC at a price of $600 or even lower when he is in need of the money.
And by selling his bitcoin on whatever the price of bitcoin. So in what part crypto currency can't be successful to individual when there's a need of money. That's why you will sell your bitcoin or alt coins in able to have something when you are in need.