Agreed, this conclusion is a non sequitur. Regardless of what the average success rate is, some players and teams are more skilled than others and will consistently succeed at a higher rate. People are much better than 50-50 at predicting which team will win a game (and there is a large industry centered in Las Vegas which depends on accurate estimates of these probabilities), which shows that it's not just random

This is not relevant at all. I am saying that there will be a 0.5 OBP for the game as a whole, not for specific players or teams. The statistics I am talking about having nothing to do with predicting variations in talent within the game.

I actually conjecture that the two of you are committing a non-sequitur by bringing in gambling odds. Do you have statistics about how successful gambling odds have been at predicting the winner or the point spread? Just because there is a business that dreams up the odds does not mean that those odds wind up actually being good predictors of the game. Why do we have million-to-one upsets every season if this is true? Wouldn't we have to wait for millions of games to have upsets of that magnitude?

The statistical regularities I am talking about are properties of the whole competition itself. And I specifically mentioned that one of my premises is that talent distribution is more balanced in pro sports than in college. How accurate are these odds predictions in pro sports? And how much more accurate are they in college? If college is significantly more accurate than pro, then that certainly is Bayesian evidence for my claim.