Up until i retired in 2019, we used POTS (Copper wire, plain old telephone service) as our redundant, back up service in the hospital. We had “direct” lines to every floor. Our main service was all Voice over IP, and it was located in Ohio…while we were in MA.
One day a back hoe outside of the facility in Ohio dug up a fiber. We lost most of our telephone service in New England.
There was hell to pay for that! Putting all of your eggs into a “cheap” basket can bite you in the rear end.
Sometimes the old way is the most reliable.
Copper is good as long as the wire is replaced when the insulation deteriorates and is no longer good. The problem with the old land lines is that the insulation goes bad and water gets in the wires causing them to fail. Yet the phone company does not want to invest any more money in that system. Therefore it has become totally unreliable.