On rereading the thread, maybe I'm just misreading? I read your question as "they're popular, why do people think they are not" but you could also have meant "why doesn't anyone want them".

For the latter: because it's far higher friction than a phone call (or any similar tool). On the extreme end, I can walk into a meeting room and push a couple buttons and have a zoom meeting. And doing that with your computer or phone is significantly easier, often just one or two buttons whether you're a two person business or 200k.

Versus telepresence robots at the simplest: it requires charging, far more complicated UI to do anything that a video call cannot do, and is many times more expensive so you almost certainly do not have one everywhere you have a video-call-capable display. And the display is probably dramatically smaller, so you still need a separate display if you want to show anything useful. For very nearly everyone, that's just "a video call with extra baggage".

They can work just fine where those tradeoffs are offsetting vastly more expensive and higher friction things, e.g. in highly specialized surgery, and you do see them in those areas. That's just a rather small niche compared to "has a computer or phone".