No, no.
Your argument absolutely holds water.
A .45 is 8 +1 standard mag or 10 +1 Wilson mag.
Definitely bigger holes, more cavitation, especially with quick follow on shots, closely grouped.
You definitely have superior fire power but, your load out suffers compared to a 9mm, for the reasons you pointed out.
I also prefer .308 in M1A but, again, bigger holes and short comings compared to a .223/.556, which holds more rounds standard, weighs a whole lot less as does a full load out of 180-220 rounds.
typical AR has 20 round mags and will deliver twice as many rounds before I reload, if I don’t drop from exhaustion of carrying a similar load out.
My mags are steel compared to polymer mags and 10 rounds of .308 weigh more than 20 rounds 223/556.
for both my preferences I pay horrible compared to the 9mm&AR dudes.
But, my theory is shoot a man with a big bullet and be done with it, as well my hope is to be 500+ yards away....
like that’ll happen.
“typical AR has 20 round mags “
Since when? 30 rounds is the standard mag.