Thousands of people competed in the London 2012 Olymics. How many names do I remember? Maybe three. How many names does the average person remember? Could be 10.
The average competitor didn't get a medal. No one remembers them but their family and friends. Those who did get a medal, I don't remember, and I barely care.
The point is, they can work hard, but for what reason?
Fame? Unless a world record is made, fame won't last very long.
Money? Working four years, (maybe more, maybe less) for a chance of maybe $100,000 (4 Golds)? Doubtful, unless they're really good.
Power? I don't think so.
Chances are, it's for fame or for fun.