It seems evident we need to be setting down our autos and going belt-fed if we really want to be safe. If our focus is on multiple attackers, then we need to change from shooting to ways to effectively evade, take cover, and change the situation to our advantage.
Cee Zee, I've been shot at, I know the sounds of bullets zipping through underbrush. I had no idea how many, just that it was a truck at dusk on a property I was on in South Alabama. All I could do at the distance (perhaps 40 yards) was to hunker behind a pine tree - perhaps 20" in diameter - in the brush. They left.
But this I know, one man versus 7, no matter how many rounds you have, is a game-over scenario. 7 men with 5 shot revolvers beats one man with two 15 round Glocks and five magazines each.
In multi-assailant scenarios, there just is simply no way to have the advantage other than with an ambush situation where you shoot first - something we know is already on the thin line of prison time. Round count becomes irrelevant.
How many rounds does a man need against two? A pistol with a 24 round extended magazine against two men with 6 round revolvers is still terribly under-gunned. A man can only shoot at one man at a time. Doing battle with them is either dumb or desperate. Two shooting at him puts the odds so decidedly in their favor that it really doesn't matter what he has.
If we are going all Charles Bronson, then I suggest it is better we discuss how to dig holes under our cabins to hide in so we can blow up our cabin safely. And if we are talking home and hearth, a shotgun (oh, sorry, that's so passe as well, right, let me change that to a tacically-loaded AR) gives advantages to the home-owner, as does a rifle.
If there is more than one assailant, the odds are so badly in their favor that round count is utterly secondary. If we are planning for that route, we need to include daily body armor carry as well.