The AK was a stroke of luck. The previous mosin-nagant was a typical shoddy piece of work. Outside of the BMP, the Soviets had crappy equipment. What they did get right like the RPG 7 was stolen again from the Germans.
Ah yes. Charles F. Kettering (the man who is responsible for you being able to start your car among numerous other contributions) attributed his success entirely to luck, then he went on to observe that the harder he worked, the luckier he was...
Speaking broadly, Russian engineers and inventors are geniuses individually.
Working in teams, less so. Getting teams to work with other design/production teams, even less.
Getting those project groups to work with the bureaucracies that fund them, the salesmen who hype their wares, and the grunts in the field who use the finished product, even less still.
The Russkies put up Sputnik because of one man. The Russkies have the AK-47 because of one man.
Getting away from the “one man” does it concept, however, proves increasingly problematic for them.
But if you have one Russian programmer doing some software for you...it’ll work just fine. Or if you have one Russian engineer designing a single mechanism...it’ll work just fine. Or one Russian playing you in chess (Xoroshow!).
Obviously there will be exceptions to the above, but that’s the prevailing stereotype.
And hey, the rest of the world all thinks that we Americans are all fat, lazy, spoiled, rude, arrogant, idiots...so stereotypes cut both ways. Gotta be careful putting too much faith in them.