[1] How could the author of the article failed to mention the Stg 44, the granddaddy of ALL assault rifles [7.9 cal, I believe] in the article? Nor does he mention the German Army’s study of infantry combat that led to it’s development.
[2] The Army’s Spec Ops guys have gotten Remington to develop a 6.8 round they’d like to see in use on an M4 platform. So you’re pretty close to getting what you’d like, caliberwise when it gets adopted
Seems like a weapon that was very much ahead of it’s time. Good thing allied forces didn’t come across them in much greater numbers and earlier in the war.
He also didn't mention the effect of volume fire by the "puny" Soviet PPSh41 on German thinking either.