I imagine the medical bills for all of them long ago surpassed the total prize moneyh.
American Ninja Warriors took the concept of a nice little show, and ruined it. Same thing happened with Iron Chef. No charm, no humor. Why bother?
The contestants seems 1) un or under employed; and 2) quite frequently nuts. Still, it is worth it for the shirtless guys. They don't seem to understand the show changes the obstacles with every trial just to trip them up, the point being to prevent anyone from ever winning.