The promise, the allure of economic stability.
I think it's the other way round. I think physical superiority is irrelevant unless it can be transformed into material gain, and thus status. Without the cash reward one is really just a dumb jock.
The difference between idealist amateur sports of yesteryear and profane professional sports of today is, at its core, a class difference. The poor did not partake in competitive sports until professionalisation, until money was to be made (they quite simply couldn't afford to!). And often despite severe disadvantages.
In that sense a return to amateur olympic competition - a topic that comes up every four years because of politics, corruption, doping or some other scandal - would be pointless for just about everyone, because there would not be any tangible reward for anyone. Love, ethics, honour and fairness do not pay for mansions, limos, supermodel girlfriends and bling.