the conventional wisdom was always that the cold war era land battle calculus went to NATO/US because of it's well developed NCO corps. the adversary was thought to be a 'hollow' force of conscripts who lacked professionalism and had few career soldiers who were capable of leading new recruits and effectively implementing the will of higher command.
This way of thinking and this manual which enshrines the thinking of the day may seem out of date and was hotly debated at the time seems to be pretty spot on judging the performance of the adversary in Ukraine.