I've actually worked a long time in tech as an SWE and with most of these groups and I'll explain the 50 Russians angle.
Scandis, Japanese, DACH, SK, Meds
They're simply not good enough vs the field to make up for the lower numbers
Russians
They're the best programmers I've ever worked with. They have the creativity/innovativeness of Euro whites and the detail oriented, technical brilliance of East Asians. Thank God they're ruled by crony assholes and communists or else they would have my job. 50 of them will do just fine.
Chinese
Technically brilliant but not imaginative, innovative, and no care or respect for best practices, there's a reason they're more into hardware than software
Balkans/Argentinians
No real opinion they're not really represented in tech
SEA
Just a shittier version of Chinese/Koreans, like hiring Mexicans to write your software, this is a quality first industry and it's a bad idea
Brazilian/Indians
Too retarded and slop-happy, no taste or standards
Africans
LOL