It isn't outdated, it is an economics definition of a monopoly, and isn't even that: a monopoly is perfectly fine, AS LONG AS the economic power isn't abused to prevent competition which harms consumers. What the author is proposing is that regulation is no longer based on economics and economic power, but on a vague definition of monopoly, and people are absurdly trigger-happy when calling something a monopoly. The…
However I believe the reason nothing changes despite these obvious market distortions is that super profits are self perpetuating: companies invest in politicians to keep the distortions in place. The technical definition of monopoly is just a smoke screen.