I guess it's not that hard to be able to maintain bitcoin for a long period especially of you know for sure that it's value will grow exponentially over time . It's like making an investment with 0 efforts , all you need to do is just wait and your funds will grow by themselves . Bitcoin is the currency of the future and sooner or later people will regret not onvesting in it .
At the very beginning it was impossible to forecast such an exponential growth, nothing was less clear than the future of bitcoin. So if you entered at let's say 1$ face value, when the price topped 350$ in 2013 you already pocketed a nice 350x upside. If you invested 1000$ at the beginning you turned to get 350000$ in you wallet few years later: that's a decent amount of money! You would certainly have used it to buy a house, stocks, a new car... it's hard to imagine you would have kept this volatile amount of money in you wallet given the uncertainty of the currency.