> Since those who are predicting have to now construct their bets such that they know they can always get run over by an insider.

The average person does not do this. People trade individual stocks all the time, despite every other market participant (banks, hedge funds, etc.) having better information and technology.

It's why institutions like Citadel pay for retail order flow. They know that retail traders don't have an edge and, if anything, often end up being negative signal.

No but sophisticated traders will also get stomped by this. Just because you're a sharp oil trading shop doesn't mean you can combat an insider who knows when Brent is about to spike in price due to insider knowledge.