Good athletes are in high demand. Owners will pay very large sums of money to have a winning team. It's as simple as that. Entertain 50,000 adoring fans, win the game, and try not to scratch your new Mercedes Benz on the way out of the parking lot. And that brings me to my next point.
Pro athletes compete in a game.
That's what they get paid for, but none the less, it's still a business. Every time a viewer turns on the T.V. and watches some kind of sporting event, a major economical transaction has been accomplished. Millions of dollars are involved. Numerous companies pay the team to endorse various products. Clothing and apparel companies pay the team to make jerseys, shirts, hats, etc.