> do they immediately get broken up?

Yes. Always. At all levels. I might provide a limit below which that doesn't happen (like $50 million in revenue), but as soon as you cross that limit, scrutiny should be automatic.

> This is a very extreme solution, and eliminates many of the benefits from horizontal integration even when the benefits are passed onto customers. Consider: - insurance companies - banking

There is no advantage to horizontal integration for consumers in those industries. If anything, the value is negative. The fact that people are quite a bit happier about credit unions than Chase says everything you need to know.

Sure, there are "efficiencies" to be gained by horizontal integration. What we have seen is that the horizontal integration is so strong that the industries are sclerotic in the face of crisis or change (see: toilet paper manufacturers in Covid who couldn't switch gears). It has become repeatedly clear that we need resilience and competition more than we need efficiency.

> utilities

Should be limited to natural monopolies and strongly controlled by the government. We have seen what happens when you create hybrid-type utilities that try to have some existence in the market (rather than being solidly government regulated) and the result is poor (see: PG&E).

Because it's like 1000x more efficient to move stuff on water vs land, so industrial cities clustered around ports and rivers since it's way easier to move stuff around.

Big cities aren't typically in such an ideal planar geological setup as that. I'm having a hard time imagining how something like that would work in the Bay area, NYC, Seattle, Miami etc

Because it trades most of the benefits of cities for the hassle of suburban life and less efficient food production.

Because of perverse incentives

To be fair, Alexander was writing in the seventies, long after automobiles and the suburb had killed any hope of humane urban planning in the States.

Utopian optimism really has fallen out of style, I suppose.

Do you see there being a realistic alternative?

I realize we can't really go backward in time, but I would prefer if the farmers that lived close to where I am sold to people who live local to me. That can happen to some degree (open yard stands), and I like to do that for some of the smaller farms, but it's really a kind of "nice to have" rather than a "The market stocks stuff that was grown a town or two over" type thing. I feel like something probably got lost when that kind of arrangement went away.

There's still one or two local businesses that manage to make it into the local market for me which is neat to see, but that's more so because they are for frozen pastries and stuff, and can prepare a metric ton in advance, and the market can mark it up for being a "local specialty" type thing. I like to buy them when I can afford it. It just sucks that essentially every other thing on a shelf probably wasn't even made in the same time zone or hemisphere.