Earlier quoted context omitted.
I always have a problem when folks bring up idiocracy because the of the eugenics angle. It’s extremely unlikely that people are getting inherently stupider, just less educated. The former is some sort of prophecy of doom and the latter is actually actionable.
Not claiming that Idiocracy is accurate, however IQ scores have been declining. https://www.ncbi.nlm.nih.gov/search/research-news/3283/
While genes must play a part in this (if they didn't, all non-humans would also share our IQ*), genetics shift on a much slower timescale than the entire history of IQ tests.
* This pattern matches to the Motte-and-Bailey rhetorical technique, ergo I am suspicious of people who try to tie genetics and IQ until they're clear they're not making a racially charged claim. Last I checked, there is no real evidence that human races are a meaningful genetic category, let alone that anything usually described as "race" correlates to any genes connected to IQ scores.