"unless fiber somehow makes its way to a farm miles from any town"
If you have a copper phone line, you should have fiber at some point. It's the same price to install (in labour), cheaper than copper, less likely to be stolen, less prone to interference and FAR lower maintenance.
Most telcos have already run fibre to rural concentrators that backhaul your voice calls to the switch somewhere else (most rural "exchange" buildings ceased to have any switching in them a very long time ago. I was one of the people who went about removing them 30 years ago when pretty much the entire world moved away from such things) . The next step is to run fiber the last few miles when the copper finally rots out.
Some concentrators are only about the size of a beer crate and fan out 24-30 lines (T1 or E1) for a few miles, on the end of a 20 mile fiber run. With 90% of faults being on the copper side, Telcos have been eyeing up getting rid of that for years.