I think, more specifically, they thrive on high repetition rate, high platform retention, and high commoditization (or, equivalently, low provider retention.)

Hair cutting/styling, AFAICT, has fairly low repetition rate for most users, and low commoditization / high provider retention (and that's even more true among the segment of the population which does have a high repetition rate), and so the utility of the market platform seems pretty low for most users and providers.

Many people get them every 2-3 months but there's a large amount of the population that go to the barber shop every week.

Maybe for a certain set of guys, but not in general. [edit: people find who they like and stick with them - high retention and reputation gets very important]