The tautology is that business inefficiencies are costs, either future, current, or comparative. Saying that inefficiencies will be punished in the long term is

The tautology is that business inefficiencies are costs, either future, current, or comparative. Saying that inefficiencies will be punished in the long term is tautological, you're just restating the definition business inefficiencies. As far as economists making that argument, take a look at the strong and semi-strong EMH. Plenty of economists agree with the semi-strong version.