Is this perception in American media (especially video games) the result of German accounts of WW2 and American accounts of the Korean War or is there a longer history to this stereotype?
/u/Elm11 has previously written about Red Army Reserves in 1941, an answer that holds up well.
/u/Georgy_K_Zhukov has previously written about the historical accuracy of ENEMY AT THE GATES and the use of barrier troops
See also How was the relationship between West German commanders and soldiers and their allied counterparts just after WW2? to understand how German accounts of WWII influenced the Western perception of the Eastern Front and the Soviet military. /u/kieslowskifan helped too.
There aren't as many archival answers about China.