I have friends who live within a handful of miles of DC with ZERO wired infrastructure. Fortunately that part of the US is pretty flat, and an LTE provider decided to cover the area.

Mind, they're about 1 mile from a major highway, so it's not like they're in the back woods.

The cable company was paid to build to that area 40 years ago, but never did it.

I agree building out wired infrastructure seems to make the most sense, as it's pretty robust, and we're often finding new ways to increase effective bandwidth (even on good old telephone wires). But it's a bit of chicken and egg, like any network infrastructure (water, sewer, roads, bridges, etc).

Edit: Keep in mind over 60% of the US population resides on the East Coast, between Boston and Georgia. So building infrastructure there is high bang for the buck.

One of the desert communities.

Sweden got fiber to small communities and towns 20 years ago