A bigger, stronger, more co-ordinate and athletic person will ALWAYS beat someone with comparable skill and less athleticism.
This is just a fact.
Actually no, and just about every NFL and NBA coach will tell you so. A bigger, stronger, more co-ordinated and athletic person will sometimes lose to someone with comparable skill, less athleticism, but who performs better under pressure, or is more motivated, or is just mentally stronger.
As Yogi Berra said, "Ninety percent of baseball is half mental". You're discounting the mental aspect, and you don't have to listen to many high level coaches in big money sports to realize how important the mental aspect is. Its why underdogs sometimes come up with the big win despite being out attributed by the favorites (in both athleticism and skills come to think of it).
Different sports require different kinds of mental toughness. Pain tolerance for instance isn't as much of an issue in say baseball as it is boxing. Concentration on a single event under huge pressure (like a curve ball coming at you in the 9th inning in a close World Series game) isn't as much an issue in boxing as it is baseball.
So all the great athletes are going into boxing since the highest paid athlete on the planet is a boxer?
Actually probably golf, since that seems to give the highest career earnings (golfers last a lot longer than boxers, and there are more of them earning huge amounts of money). If its about money, the way to go is definitely golf. And look at all the superstars in other sports (Jordan, Gretzky etc) who play golf all the time now and joke about how bad they are at it - obviously golf takes huge athleticism.