This is not a problem in multiplayer video games with voice chat because I think they somehow manage it with multiple simultaneous audio sources. I'm surprised that Zoom has not done that yet. Just do what video games do.
https://support.zoom.us/hc/en-us/articles/115003279466-Using...
I think the catch is that people need to be on headphones for echo prevention, which might be the case for most of the gamers.
This kind of mixing won't work well in a game for obvious reasons, so the audio is sent direct. However, the game uses direction and distance based audio to make the sound more natural. E.g. if the player to your right speaks, the signal you hear will be panned to the right. Humans are great at identifying different voices coming from different directions - you can try this yourself by loading up some voices into a DAW and seeing the difference in intelligibility having them panned out vs mono.
Note that this tech may work well in a VR meeting room or something but it won't in a regular monural video call. Also the user will need a proper stereo setup (headphones or speakers a reasonable distance apart) for this to work.
You don't need a VR meeting room to simulate the same idea, it'd make the call so much realistic and easy to follow.
FYI that is fairly atypical. Mostly in mil-sim type games like ARMA, or VR games. Most in game voip is just a mono source played through both stereo channels equally.
By default it’s setup like a game. Audio in both channels. It can be (and often is) extended.
The same issue has plagued cheap camcorders with no manual gain controls for a long time too as they crank up the gain whenever there's silence - making their audio noisy garbage even if the ECMs and pres are adequate.