The core strength of our military is that we put a lot of power in the hands of career NCOs, who are literate and often carry more knowledge in their heads than the boot lieutenants nominally in charge. We even have a Warrant Officer track for technically minded NCOs.
The no-career-NCO Soviet Union style military which most of the Arab nations have embraced is a serious hindrance, and it's notable that Russia did away with it in 2008, leading to better military unit performance in recent conflicts.
I would guess that the Soviet military system was originally adopted to balance the need to utilize an illiterate uneducated peasantry while at the same time denying them any real power or opportunity to move up the social ladder.
It is interesting to me that the system persists in many of the U.S.' allies today.