In the sense of the Sherman Act and similar legislation, monopolies exist in the sense of having exclusive control over some supply and raising prices against consumers.
This isn't what Google does, they generally lower prices for consumers and the competition is only a click away.
The consumer harm standard is an outgrowth of the work of Robert Bork, who was Solicitor General for Nixon and Ford, respectively.
It was not established by legislation but rather as a matter of conservative legal doctrine. Before Bork the commonly held evaluation standard was based on the Rule Of Reason.
The Sherman Antitrust Act didn’t establish any guidelines for how it was suppose to be interpreted (the whole thing is only a few pages in length) and the Clayton Act only expanded upon what actions could be considered as part of an Anti trust case.
The consumer welfare standard has no basis in legislation, only legal doctrine.
It’s unfortunate we haven’t codified anything more concrete, as the consumer welfare standard has a number of flaws, as admittedly did prior legal doctrine.
The Rule of Reason was more rigorous, though not flawless, as far as market competition goes though, my view is it is a better legal doctrine overall and could be updated to better address todays and future concerns, particularly with digital goods and technology.
I judge this Chicago-school-pushed shift in antitrust enforcement so bad that I usually mark it out as the first noteworthy step on our current thrust toward authoritarianism.
The market consolidation we've seen since, and the concentration of power, have been absolute poison for both liberal democracy and the good aspects of capitalism, so far as contributing to the common good.
Odd, then, that this is the second case within a year where Google has been found, in fact, to have violated the Sherman Act. This suggests that
your description of what the Sherman Act means, or of what Google does (or both) are wrong in significant ways.
The consumer of the ad platform is the advertiser, not the person clicking the ad. Major advertisers either play ball with Google or their ads don't get seen in search. Doesn't seem very different to Standard Oil controlling who got access to refineries.
Aren’t they? It doesn’t sound like those two interpretations are mutually exclusive.