I didn’t forget the rate reducer because the Russians also played with a rate *increaser* in the AN-94 variant, with the ‘stupid fast two round burst then normal autofire rate’ system - so they’ve gone to both ends of the spectrum.
I think that governments/militaries using standing automatic fire as a test is less of a replication of a commonly used combat mode and more of a lowest common denominator test. It’s the most difficult stance in which to control an automatic weapon, so if the weapon can be controlled while standing, kneeling or prone unsupported fire will be easier. They do have a point there.
On the other hand, from what I’ve read and from what I’ve heard from others, it seems like open field combat may be less of a thing in the future than in the past. It seems like urban warfare, house to house will be more likely, given the increase in number and capability of overhead sensor systems. Even against skilled professionals, standing, crouching or kneeling autofire is something that needs to be employed. Prone is not that useful in such situations, I am told.
If you are acquainted with WWII history - and Korean War and some extent, Vietnam - then you are also aware the really massive firefights are fearsome things. Besides the hundreds of rifle caliber weapons, there were mortars, grenades, shoulder-fired rockets, and artillery of all calibers.
Don’t just consider the types of limited combat we are seeing recently as the norm. The future could very well be North Korea again, or Iran, or even China with all of the mass and weaponry that we could see again.
It’s a perennial question in small arms design: long reach and precision versus high volume and “hit probability”. The StG44 started the revolution towards high volume of fire, stand-while-firing weapons and while they are attractive and handy, the long magazines preclude prone firing and the short sight radii preclude precision engagement.
The arguments will go on, but I can tell you from experience that firing from the prone helped me stay alive - and let me hit what I was aiming at.
Don’t assume that the current evolution is the best direction. Remember - StG44 or not, the Germans lost!