zlacker

> This is the exact sort of thing anti-monopoly laws are intended to work against: that a major market force in one market uses that power to intrude or support itself in another market.

That's actually not true. There's some case law about that sort of thing (the Microsoft antitrust case being the most famous), but the basis for anti trust law has always been about price efficiency, not protection of competition for competition's sake (c.f. the Microsoft breakup was overturned), nor consumer benefit.

>>ajross+(OP)
The case against Standard Oil was pretty explicitly because of anticompetitive behaviour, not price inefficiency.

>>joelwi+Yi
The anti-competitive behavior was creating price inefficiency. Standard Oil owned almost the entire refinery market, and they were colluding with railroads so they effectively owned distribution. This vertical alignment meant they could effectively set whatever price they wanted because there was no other game in town.