So I'm up by 1 with 20 seconds to go in game 7 of the finals and I foul you. You really think I'm gonna hand over my championship out of fairness?

This would turn every professional sport into the UFC.

There are refs in UFC.

Are you serious? This isn’t how incentives work. The more money is on the line, the more you need refs.

This is true regardless of who’s playing or the culture of the sport. The only reason ultimate frisbee doesn’t have refs is because no one really cares about it.

You can't do that when there are $billions on the table. What happens when someone cheats?

You'd need to find some way to allocate that money other than "to the winners". And/or, you'd need to disqualify or otherwise punish cheaters so strictly that players aren't tempted to do so.

Then again, I confess I really don't understand pro sports.