"That person who said the pen was mightier than the sword obviously has not encountered automatic weapons!" - - D. Mac Arthur.
It should be well understood that modern technology/design and the industrialized form of warfare as practiced during both World Wars has allowed the major powers of the world to equip their combat units with infantry automatic weaponry in profusion.
The squad level automatic weapon in whatever form becoming the primary "tool" as available to the infantry squad, the rifle as carried by other combat troops a secondary and supporting weapon.
Mechanization and industrialization and the capacity of the military complex to produce an abundance of automatic weaponry resulting in a greater and greater number of troops being issued rapid fire weapons of some form.
So much so that entire units of Soviet troops at the end of World War Two [WW2] were found to be equipped, each and every man, with a sub-machine gun, the PPsh. That PPsh firing a pistol round, 7.62 X 25 mm, entire units on the assault possessing what must have seemed to the defender to be overwhelming firepower.
"The Soviets would often equip whole regiments and even entire divisions with the weapon [PPsh], giving them unmatched short-range firepower."
[the average fire fight between infantry during the Second World War was said to occur at a range of 200 meters or less. Under such circumstances, the PPsh was the ideal weapon in many regards!]
The experience of the Soviet was, however, that arming each and every combat troops with a sub-machine gun did have drawbacks, to include:
* NOT effective at longer ranges.
* NOT having the desired "stopping power".
* EXCESSIVE expenditure of ammunition.
[with regard to the expenditure of ammunition, recall the admonition that lieutenants think tactics, generals think logistics.]
That PPsh ["burp gun"] as used by communist troops during the Korean War, also confounding American forces, the latter often in an infantry engagement finding themselves sorely outclassed by the massed firepower of an entire enemy unit each and every man equipped with a sub-machine gun! The PPsh giving a lot of grief to American infantry commanders!
"Though relatively inaccurate, with a high rate of fire, the PPSh-41 was well-suited to the close-range firefights that typically occurred in that conflict, especially at night. U.N. forces in defensive outposts or on patrol often had trouble returning a sufficient volume of fire when attacked by companies of communist infantry armed with the PPSh-41. Some U.S. infantry officers ranked the PPSh-41 the best combat weapon of the war; while lacking the accuracy of the U.S. M1 Garand or carbine, it provided more firepower at short distances. As one infantry captain stated: 'on full automatic it sprayed a lot of bullets and most of the killing in Korea was done at very close ranges and it was done quickly - a matter of who responded faster. In situations like that it outclassed and outgunned what we had.'"
Modern assault rifles as issued to the combat troop do have a selective fire capability, that most recent version of the American M-16 having a three-round burst capability. Most infantry units only allowing their troops to use semi-automatic fire, that three-round burst used during urban warfare or under the most dire and desperate of circumstances.
Depending upon the circumstances and type of combat, the PPsh was an ideal weapon, but not universally so? Such must have been the conclusion of the Soviet when the AK was adopted as the standard weapon? And from that point on, the assault rifle and weapon as issued to the ordinary combat soldier has continued to follow the AK and M-16 model. And for the foreseeable future, will continue to do so!