I have many smart, empathetic friends in tech who are not having kids. Meanwhile my redneck neighbor has 5.

It seems to me that all of the conscientious people who look out for the greater good and environment, are leaving the gene pool. This feels like a problem for the future.

Are you somehow superior to your neighbour? Do you have evidence that your neighbour doesn’t care about ‘the greater good’?

Is there even a universally accepted definition for ‘the greater good’?

I’ll entertain that thought - How is that a problem?

I'm mostly imagining a dysgenic future similar to Idiocracy; but really, it's more of an emotional appeal than an actual argument.

The pretty reasonable copium is that the differences you're focusing on are traits which exist in the DNA of every person you see, including ones that don't exhibit those traits. They're just expressions of a random/environmentally-determined subset of the DNA within everyone.

As anecdata, wait until you meet a girl from a broken family of alcoholic rednecks who live in the woods and find out that she can code circles around you despite growing up without anything you can call broadband. ;p