They had like 300 million people population and for a long time were the country training the largest number of engineers every year. So yeah a small percentage of these engineers did turn out to be brilliant.

Its not only the populations size. Technical people were precised as prestigious and well paid. After soviet collapse, this changed causing exodus of talent to west and overall decline in numbers.

Apparently noways a lot of industries are loosing institutional knowledge/expertise built and past down by each generation. because there is no one to pass it down to.

Technical people were never prestigious nor well paid. That was not desired in communism where workers were presented as ruling class. Engineers salary was 110-130 rubles, casual worker ~70 rubles and small caliber boss ~200 rubles. Depending on workplace engineers could steal way less than workers (who had direct access to product) and resourceful bosses.

Edit: a car in comparison was going for 7000 rubles.

I believe (not an expert) that during Stalin times technical people were very well paid. But Khrushchev returned to the policy of leveling (uravnilovka) and tried to make worker and engineer salaries the same.

Fair enough. I'm not saying they were necessarily unique. And they did do a good job of doing horrible things to much of the talent that got to the top.

No shortage, but no surplus either. They just sank a ruinous portion of their GDP into that stuff.