I think part of the question is that the military realizes that the full auto attribute of the first assault rifle is not the most important or revolutionary attribute of that rifle. The ergonomics, light weight, lighter recoil, lighter ammo, and better handling are all more important to performance. Do you really need every man carrying light machine guns? When the ammunition load is limited, semi-auto makes more sense for the majority of troops.
What you are also seeing is the machine gun turning into an "assault machine gun" with the SAW and such using the same intermediate ammo. Not as revolutionary, but fits the same concept.
Also, even if we switch to a larger cartridge, it still wouldn't be a "battle rifle" to the purists on this board. That also is not a military term. Just a term people picked up to differentiate the rifles in discussion.
What you are also seeing is the machine gun turning into an "assault machine gun" with the SAW and such using the same intermediate ammo. Not as revolutionary, but fits the same concept.
Also, even if we switch to a larger cartridge, it still wouldn't be a "battle rifle" to the purists on this board. That also is not a military term. Just a term people picked up to differentiate the rifles in discussion.