[azakai]

> Intelligence and other positive characteristics don't seem to get involved in whether they have surviving offspring today the way I imagine it did a few thousand years ago.

Selection is always active.

First, there is sexual selection, not just natural selection, and there is no reason to assume that is not important today.

Second, as the article says, there is more genetic variety than before - we accumulated a lot of variation in recent millenia. That's the necessary foundation for selection.

Finally, a quick look around shows that some people have more children than others. You mention "Intelligence and other positive characteristics", but the fact is, it isn't clear intelligence was ever more important than say brute strength/social skills/etc. in our evolutionary history, so the fact it isn't the main factor now says little. But there definitely are factors that do contribute to having more (thriving) children today, and we are selecting heavily for them, for better or for worse.

[nhaehnle]

it isn't clear intelligence was ever more important than say brute strength/social skills/etc. in our evolutionary history

The juxtaposition of intelligence vs. social skills is amusing given the Machiavellian Intelligence Hypothesis, which suggests that our general intelligence basically evolved precisely as a means to get ahead in the social games that are relevant for sexual selection.

If you can reason abstractly about what some rival is going to do and examine the "game tree" of potential actions, that is surely an advantage both for sexual selection and, say, debugging or proving theorems.