>For whatever reason

It's pretty simple: as you say, they're local. Google and Amazon are the big evil corporations on the other side of the country, but Comcast has an office in your town, and your neighbour's son works for them. They're a significant provider of relatively well-paid low-skill jobs in every community in the country. It's incredibly difficult to come down on that.

Maybe, but I don't know if I buy that reason.

It seems more like the actual interest in actually doing any anti trust stuff for any consumer type product just faded away mostly ...

I don‘t think states have ever been compelled by antitrust suits to change regulations; there is no state-level version of the WTO where one can sue about this.

Remaking federal regulation to preempt states is laborious and fraught with difficulty; see Obamacare.

And yet we have the interstate commerce clause, giving the fed a direct line to meddle freely in any matter whatsoever.

Most ISPs exist in multiple states. Divvying up local markets does not really prevent interstate competition or impact interstate commerce, or at least that hasn't been tested in court.