Off topic, but, the USSR had a brutal education system (as in "good"), and lots of stellar talent. It was too poor to have the proper tools to widely cultivate that talent. At least the world got Tetris out of it.
A lot of university students in Moscow, Kyiv, St. Petersburg or any bigger Soviet city weren't actually born there. If you were from another city the university will give you dorm room if you pass the entry exams.
In case of Pajitnov luck is more about getting a job at Academy of Sciences, but probably it has something to do with his talents.
Education-wise, YES, the USSR was a meritocracy, way more so than the United States. My father was born in a God-forsaken Ukrainian village, and he studied in then Leningrad.
After you graduate, of course, it's different. It requires significant maneuvering in the political system and ample butt-licking to get anywhere serious.