What made those zip codes good?

Parents that invest time and resources into their children?

We had a computer lab with 8 Apple II's in my public elementary school in 1983. We also had a few TRS-80s.

Money.

Parent's money, to be precise.

Wealthier parents will buy homes there and donate/invest in local schools, which will afford a better education to their kids that, along with better networking, will increase the chances of being financially successful of their kids.

I think that's a terrible answer, sorry, and is pretty much what I mean. I somewhat agree with Taleb that wealth begets education, not the other way around. The special thing about good school districts is not the schools themselves, and the special thing about schools is not necessarily their budget: Some of the worst performing schools have the highest budgets.

White flight.

Correlation does not imply causation.