Imagine an investment model which guaranteed to do better than the market.
Then if everyone applied the model , it would stop working, since by definition doing better than the market is a zero-sum game.
Then, the competition would be in applying that model with the fastest computers, or would be in essentially attempting to manipulate the market.
Alternately, this simply would mean that the model expires and thus that any model for investment is temporary unless it is kept secret.
Thoughts?
This is math and science, the question is whether one can disprove the existence of a permanent perfect investment strategy by a thought experiment.