Well, that is the (Borkian) dominant understanding of antitrust right now, but it hasn't always been, and I think that view is under pressure again.

It has never been clear to me why we must limit our view to consumers when looking at antitrust - there is always much more going on than how much things cost. It effects competitors (actual and would-be), the environment, related industries, available jobs, sometimes national security - monopolies can have huge impacts on lots of things. Why exactly is this super-reductive, artificially crabbed view the only measure of a monopoly's harm?

Medium-term, I think the pendulum is swinging back.