Winning in zero-sum games is harder (but the reward is usually bigger)

Really? Business is generally positive sum: you win big by being unique, not by competing head to head. Sports is zero sum. Here are figures I came up with from a quick search.

Total of the 100 highest paid CEOs in the world in 2013: 3.028 billion.

Total of the 100 highest paid athletes in the world in 12 months to June 2014: 2.75 billion

I had actually expected the difference to be larger in that direction, but certainly the athletes are not doing better than the businessmen.

One could think of a lot of other possible measures; that was just one it was easy to find figures for.