"According to AK-47 legend, assault rifles were not popular because of their tendency to consume large amounts of ammo. The Soviets embraced the idea and simply supplied their troops with more ammo. Kinda like Redis and RAM."

That's obviously just a legend. This debate was actually carried out in the 2nd half of the 19th century, starting with the Civil War. (Many repeating rifle designs were offered to the Union. Quartermasters repeatedly shut them down on account of expected difficulties with ammo supply. After much time and effort, a few repeating rifles made it through, particularly to the cavalry, where they proved quite decisive in the last year of the war. See Five Forks, for instance.)