Nobody thinks the process has stopped. The argument instead is that the environment has changed over time, and some traits that once increased the organism's odds of reproduction relative to peers no longer have that effect.
Whether those with "certain ASD risk alleles" tend to have more or fewer children than those without is an empirical question, but I certainly wouldn't be shocked to find that the fitness benefits to "neurogenesis and cognitive ability" have declined.
Getting very near indisputable now:https://www.gwern.net/docs/genetics/selection/2017-kong.pdf
The decline is actually quicker than you would think, TBH. Cognitive ability decreases reproductive fitness in this environment in women but not in men, so I imagine the decline will halt once we reach some sort of equilibrium, assuming dimorphism isn't possible quickly. I imagine selecting for dimorphism in this trait, though it would happen eventually, would take too long to matter.
Not too worried as "unnatural selection" will overwhelm this small effect shortly.
Idiocracy assumes not just more education = fewer kids = more wealth, but also more kids = increased odds of reproduction and that these traits are reliable across generations.
We've proven more education -> fewer kids, and more wealth -> more education. So far as I know, we've not proven or disproven fewer kids -> more education, more education -> more wealth, and more kids -> increased net reproduction, at least not across enough generations.
Certainly these SEEM reasonable conclusions, and some have only been proven in the short-term. It might be that more kids -> less wealth -> less education -> net loss of reproduction. e.g. having 12 kids does give you more chances to push your genes to later generations, but the odds for each kid to get to reproduce are not the same as if there were fewer kids. If that difference is big enough then too many kids is a losing strategy. (in agrarian economies children are a resource, but if children can't work, the odds of the entire families' genes passing on are reduced for every new child past a certain point)
Idiocracy also assumes that intelligence is highly hereditable and highly correlated to wealth - In reality that connection is far fuzzier (likely technically true, but at such a low degree that environmental factors can easily matter more)
Still though - it was an amazingly effective communication of a complex topic. And I'll admit that there are news stories I read that stir my hindbrain into hear the little "bloop" noises of adding to the family tree from that scene.
Basically it is relatively easy for the environment to push an individual below their potential, but near impossible to pull them above once a basic minimum is met.
Intelligence might correlate with wealth in societies with free markets... but lower classes in a stratified society won't have access to resources that translate intelligence into success.
There are two pathways to selection. You're only focusing on one. Sexual selection is alive and well.
Consider something like a "Highlander" allele, that has a chance to randomly appear in the general population, granting them the same stipulations as in the movie. Given that there can be only one, this particular allele has terrible reproductive success in the sense that practically no offspring will ever survive. However, the gene will always tend to exist in the population. Now, if there is some event that occurs that increases the maximum of number of Highlanders, this event will put positive selection pressure on the allele, even though the general population can reproduce much faster.
All that said, fertility rates among the middle class are not zero. They may be below replacement rate (ok, they are below replacement rate), but being non-zero means evolution still applies.
Also, obviously in the wider population (that is, world-wide) we might well be selecting against traits that lead to middle-class status (by having lower fertility rates in the middle-class), but still, within middle-class populations we're likely still selecting for those traits.
Unless the middle class is a separate population to the rest of humanity then the evolution that is happening in the human population right now is selection against traits that lead to being middle class.
This selection is probably the strongest of any in human history looking at the demographic trends. When looked at dispassionately it is truely breath taking how huge this is.
>> Accordingly, we hypothesize that certain ASD risk alleles were under positive selection during human evolution due to their involvement in neurogenesis and cognitive ability.
I don't think they "were under positive selection", I think they still ARE. So many people like to think that humans evolved to our present state and then act like the process has stopped. The wording here echos that a bit.