Comment by Doxin

In my experience that's mostly a function of how good the acoustics are. In a place with a lot of reverb that is definitely what happens.

On the other hand I've been in one or two restaurants with really good acoustics. You could easily have a conversation in those even at the busiest of times. If there's no reverb your voice doesn't bounce all around the room. Your table can hear you perfectly fine, but you're basically inaudible to someone a few tables over. The background noise sounds like a pleasant murmur instead of a loud cacophony.