There are a few technical hurdles that must be overcome for "everyone wears a headset to work" to work at all.
* The headphones must block outside sound sufficiently, so you only hear the people in the same room through the call and not directly.
* Your headset must not pick up when other people in the same room are speaking.
But even then, it has serious drawbacks compared to an in-person meeting:
* Latency. With anything over a 50 ms roundtrip (including hardware), people inadvertently start speaking over each other, and typical latencies are much much higher than that. It becomes more difficult to break into a discussion, trying to make a small interjection often disrupts the flow of conversation.
* Lack of non-verbal communication. Webcams remedy this to some extent (though many are negative to using webcams in their home for other reasons).
It can be argued that this is a small price to pay for the ability to WFH, but it's disingenuous to say that pushback against "everyone on headset" is just due to people feeling "daft" doing it.