>Ultimately, the relative decline in height isn’t substantial or definitive.
>People who live in wealthier countries and therefore have better access to nutrition, have fewer children. This could mean that the benefits of living in prosperity — better nutrition — might not be passed onto future generations.
You should learn the difference between sexual selection and natural selection. When a trait successfully passes on to the next generation it's not indicative of sexual selection strategies, but of natural selection.
As I said above IQ is similar to height, where it's associated with desirable characteristics a female would pursue but is actually not naturally selected.
It's when both the sexually selected trait aligns with naturally selected ones that evolution succeeds and becomes s functional trait. For example, longer necks are very attractive female giraffes but it's also a functional trait for giraffes.
Currently the sexual selection strategies of humans don't align with that of the nature because of the existence of contraceptives that cheats it.