The core concept of it, effectively it is eugenics, IQ etc...
The real part of it is, it's not eugenics, it's education that's hitting the spiral. Poorly educated people, keep getting convinced to make education less accessible and worse, leading to more poorly educated people, that vote harder on it, ad infinium.
Bottom line, religion and power structures have found education as their target to limit, and have been for decades.
I do agree the opening of idiocracy really presented some extreme "eugenics" vibes to it. Which also is kind of weird because the end of if basically presented the opposite. Where not sure in his mediocre knowledge starts pushing for education improvements, improving the culture etc... Not sure's conclusion at the end was basically that everyone is ignorant not dumb, and society could gradually be fixed by actually trying.