I certainly do not miss the ability for only one person to speak at a time on a phone call. Wonder how many people remember their last phone call like that (on cellular or on cordless).
What do you mean? Like either you speak or the person in the other end speak? That I don't remember! Was that a restriction on early cellular and cordless phones? Our phones had cords.
I remember we had only one line going into our house, but several phones, so if one picked up one of the other phones one were in the same call.
I don't recall 2s latency, but do remember 0.25-0.3s latency one way for transatlantic phone calls in the 90s, which happens when the call got related over geostationary satellites rather than over Atlantic cables. It was basically a 0.5-0.6s roundtrip delay enough to cause you to talk over each other.
It only happened when there were too many callers at the same time. The solution was often to redial and hoping you ended up with a non-satellite call.