It's really surprising to me how little uptake 2600 ultimately ended up having.
There were also specialist circuits (e.g. EPS) where you had a physical line from end to end (with a couple of amps along the way on longer runs).
We also had some large campus type sites where we would sometimes implement EPS to do LAN extension over the onsite twisted pair as it was cheaper than installing fibre and just about fast enough.
"Strowger, an undertaker, was motivated to invent an automatic telephone exchange after becoming convinced that the manual telephone exchange operators were deliberately interfering with his calls, leading to loss of business."
I wonder if the phone company was actually out to get him!
There's a great video from Connections Museum (mentioned further up the thread) where they're going through the operation of, I want to say, one of those crossbar switches? And they start using terminology like "routing table", "longest-prefix matching", and "default route", which all sounds well and good, until you realize they're talking about systems that existed decades before the Internet or even ARPANET, all electromechanical... Dope stuff. Cool to see how things rhyme even as they change.