I can substantiate this from my own observations. I trained with many Russians over many years (not the crazy, skinny kooks you see on youtube), a lot of ex military whom believe in that cyborg, linear mentality when it comes to combat , and they believe in one thing only -- muscle memory (especially when it comes to breathing, as stress can restrict breathing).
Look at it form this perspective. All Russian males have to do military service. They all have to do 'the field', so to speak, whether at home, or stationed abroad in a foreign country. In the military, they want to create a body dynamic that performs on muscle memory alone, especially when the mental capacity is overwhelmed by either fear or information bombardment -- only the body goes into action, precise and accurate, without having to think.
So you can see, since all males are indoctrinated into this process (the military being a sort of cultural right of passage), this way of looking at combat sports and life can easily spill over and can become a ubiquitous mindset in Russian culture, where the older males teach the young. And maybe you can argue that this has been creeping into the general population since the end of the second world war, or Stalin's era.
The group I've trained with practice techniques and/or principles precisely and repetitively over, and freaking over again, and freaking over again, so when you need it, and are overcome with fear or stress, you don't have to think about it, your body just does it.
I have noticed, nonetheless, that 'westerners' don't really have a passion for tedious, repetitive drills. I might be wrong, but that's only my observation. At the places I've trained before, the Russians quickly developed into monsters, while 'westerners' that have been at the same tasks for years and years, just either didn't excel, or didn't get it.
The Russians come already with that disciplined regimented work ethic, willing to endure the most banal, repetitive tasks, which seems ingrained in their culture, while very few 'westerners' have that same passion for mundane, tedious repetition.