There are entire countries trapped in poverty. China was desperately poor until just a generation ago. Did Chinese people suddenly become smart for some reason? Which is the next country that will magically go from being filled with dumb people to being filled with smart people?
As I said, just a bit of experience with the real world and critical thought will show that your explanation is nonsense.
Yes, they stopped following strict communism. They pivoted to authoritarian capitalism and got wealthier.
(Basically) no intelligent teenager in America is held down by poverty. My parents were relatively poor, didn't go to college, worked long hours, and I went to a public school and certainly didn't have any tutoring and didn't receive much help with homework.
I did well enough on my ACT to go to a private college for pretty close to free. Even if that doesn't happen you can go to a state school that doesn't need great grades, take out loans for the entire amount, get a degree for a good paying job, and suddenly you're out of poverty.
For some reason a large part of our society doesn’t want to acknowledge that genetics (highly) influence intelligence.