If we could cheaply and efficiently transport hot water over miles and miles like we can with electricity then communal water heating would be much more common. Note that communal water heating is fairly normal (i.e., not "absurd") in large apartment, condominium, and commercial office buildings (one large boiler providing hot water for all tenants).

> Millions of individual homes running their own solar, even with everybody hooked up for exporting, is quite feasible. It’s happening today.

The question isn't whether there's an issue hooking individual residential solar installations up to the grid--no one disputes that. The relevant question is how expensive is it to build and maintain tens of millions of individual rooftop solar installations versus several orders of magnitude fewer, larger installations. According to https://www.solarreviews.com/blog/what-is-a-solar-farm-do-i-..., it would cost at least ~$2.8M to generate 1MW via rooftop solar systems while it would cost only about ~$1M to generate the same amount of energy via solar farm.