Three factors were at play: 1)Not much dumbing down, if you don't get it, you will barely scrape through. The system was not primed for holding back everybody down because of a dumb minority.
2) A dedicated effort to identify the smart kids, direct them to focused high quality schools, encouragement to get involved in serious competitions (mathematical olympiads, but also correspondence seminars) and math clubs.
3) Not so much distracting options to do other interesting things (very unlike the west), so much easier to actually attract and keep the smart kids interested.
The education system is in much worse state now - both 1) and 3) are gone, and 2) is severely affected, mostly by 3).
(In a Russian accent) “if you throw many eggs at wall, most will break, but those that don’t are strong egg. Igor was strong egg”
He had multiple top 10s at world championships and 1 medal… definitely a strong egg
Whoever survives to the end will be a world champion.
There must be a middle ground between setting the bar so high that you will find only the diamonds and setting it so low that almost every rock out there will pass.
This isn't to say that the USSR had a better system than the West--it did not, and its collapse is testament to that. But strictly in terms of education in math, literature, science, it did quite well. Similarly, Cuba did a _much_ better job at educating its population than its Caribbean neighbors.
To me, it seems US is emotionally invested and being stubborn with the idea that natural selection and power concentration is key to competency, and universal measures are risk factors for the all-important elimination processes, despite there being ample proofs that that is not even a sane line of thinking and distribution of most things just keeps making huge returns.
Otherwise, let's assume the bottom 50% actually can't be educated, is it waste of whose time or resources to try?
The private schools would get the kids to the same place but they'd toss tons of resources at any kid who needed it to get them to that place. Unless the kid was disciplinary; in that case they'd show 'em the door.
Rock bottom was the non-selective public schools. I don't think it was that they didn't care it was ended up with a lot of kids that those first two groups wouldn't touch with a ten foot pole. Not just kids who didn't want to be in school (which would be tricky) but one's who's parents didn't care if they were in school. That enough trouble that it creates trouble for the kids who want to be there.
Not to mention, Proletarianization of Universities (Rabfaks), which accelerated prep schools attached to universities designed specifically for adult factory workers and peasants who lacked formal secondary education. They also built what were essentially trade school-like institutes to rapidly educate people on medical, pedagogical, and polytechnical studies.
I mean, it also had an academic hardcore side to get star students into positions of power and influence, but all successful societies have that. When we see these very same systems in leading capitalist systems like the US, UK, Germany, Japan, or Korea we applaud them for recognizing and empowering talent. Socialist societies are instead somehow criticized for this.
If anything the Soviets were far more serious about educating everyone than their western peers and one of the reasons they become a world power so quickly.