I saw this conclusion on a website about the sociology of finance:
“Are the purveyors of models selling us lemons? At the core of the controversy, I believe, is a fundamental question that orthodox finance has not, to my knowledge, yet addressed: what is the practical accuracy of a theoretically correct model?”
If you tell me what you mean by ‘correct model’, I’ll tell you what the practical accuracy is.
Meanwhile, I have something I once wrote along these lines: