The analogy is cute but misleading. How is par established? Is it based on the average of all professional scores? Clearly not. If the rule makers raised par, more golfers would beat it. This comparison is irrelevant.
More to the point, if the return on all assets equals the market return (an identity), then all activeley managed assets equal the market return before fees and others costs. Another identity, because all passive funds by definition equal the market return.
Where this gets hairy is recognition that none of the major indices, especially the S&P 500, equals the equity market. S&P intentionally omits stocks with no earnings, for example. I think this whole question needs a redefintion. Maybe it is simply how difficult it is to pick an active manager who will outperfom over time. That is the choice people have to make.