Back in the old days (early 90s), they actually were many-pole switches. If you opened one up, it looked like a stack of washers with a bunch of wires coming out of it, more like a variable capacitor than a normal switch.

They were very expensive and very unreliable. If something was weird, click it back and forth a few times and maybe it fixes itself.

Nowadays the signaling is too fast to go through a physical switch and most devices would be unhappy to be plugged/unplugged so rapidly.