Question is about EMH and how you expect efficiency to be achieved absent profit for collecting the information.

There are 3 accepted forms of EMH. I'm talking about weak form - just price history and nothing else. E.g. formulaic alpha have demonstrable predictive value in modeling.

All that to say you believe trading profits are real. Maybe you just need to learn more about what a buy side alpha quant at two sigma does for a living. Trading models can be robust and exploit real inefficiencies. Weak form EMH is demonstrably false on it's face, as you agree.