The only way this works is if carriers invest in a ton more hardware, which means leasing more tower space, creating new tower space, getting creative with placing radios in areas where you can't really put towers, etc.

That's expensive. What's also expensive -- sometimes even more expensive -- is running wiring to all those places to connect those radios to the backhaul network.

I frankly do not expect US carriers to go to that expense, at least not universally.