American IQ scores have rapidly dropped, proving the 'Reverse Flynn effect'

Honest question that keeps bothering me.

In the absence of reasonably strong natural selection pressure to select for IQ, how could IQ not be falling over time?

Conscientiousness and having long-term time horizons is dysgenic. People afflicted with those traits tend to reproduce less, and, to the extent that they're heritable, the genes coding them will gradually decrease in prevalence in the gene pool.