The goal is to surround your kid with the other kids who will be as good of an influence as possible. I'm not saying you won't find kids like that everywhere, but generally, the higher the income of the parents (up to a point), the likelier the parents are to have taught their kids to value education and other things that will help them succeed.

And so to maximize this probability, people stretch themselves to live in neighborhoods bidding against other people also stretching themselves to live in the "best" neighborhood they can afford.

I teach my kids that it might be a poor ROI to work for material stuff, but I do teach them the importance of wealth in being able to obtain resources in the future.