Well, again, most all groups from that era and before tended to crowd around the mic...think of The Andrews Sisters!
The response that they had no PA system begs the question...what was the mic for?
? It had to plug into something.
I'm trying to determine if the practice of sharing the mic was
dictated by the gear of the era, or, if it was a
choice due to showmanship and or a belief / fact that they sounded better.
It may be a combination of choice and gear, but you just dont see the practice as much these days.