Maybe area-dependent? I grew up in an extraordinarily rural area in Tennessee. Most roads were paved (asphalt). Even ones out in the middle of nowhere.

The conditions of some of the remote roads might not have been great, mind you... and some seemed "thinner" almost, maybe paved a long time ago?

Of course there are political factors. I have always heard that in Wisconsin many rural roads were paved to better serve dairy farmers beginning in the 1890s - and continued through the WPA program. While in Minnesota, similar rural roads remained unpaved.

Best link I could find to substantiate such a claim

https://www.uwlax.edu/currents/biking-in-the-driftless-regio....

Of course in contemporary times the high maintenance cost has many Wisconsin towns/counties considering returning to gravel.

https://www.wpr.org/economy/taxes/small-wisconsin-towns-pave...

I think it's a snow thing - asphalt seems to wear down really fast in rural PA, probably from freezing at nights and snow and ice, so you can't do paving as cheaply out in the mountains or so on. The county dumps gravel down once a year and let's passing traffic wear it smoother over time, but it sucks to drive on fresh.

Chip and Seal is a technique used in a lot of rural areas that comes in with less maintenance than gravel but not as expensive as asphalt. It is basically a a top thin layer of tar with gravel pressed into it.