To be clear then, you're not actually talking about quality of education (tutoring, robotics teams, mock trial, great teachers, enrichment activities, science museum trips, history competitions). As you say, it's "ability to prioritize what income they do have to make sure you're in a good neighborhood". Your primary problem with this, then,is that it devalues the ability to move into rich neighborhoods.

How does the ability to move into a rich neighborhood correlate with college success? I teach math, so that would be a great place to give an example.