He used to point at schools. He has since figured out that school improvement isn't the fix, and especially that throwing money at schools isn't a fix.

He now points at household income.

These are just things that happen to correlate with whatever is causing behavioral differences. I've known two poor families whose kids did fine, but those poor families were DIFFERENT from the cultural norms surrounding them. One had a mother with a fierce passion for pestering teachers, pushing to get her kid into advanced programs, and getting her kids to work hard. The other was a strict homeschooling family. Both of those families would not accept anything less than the very best that was possible.

It is easy to suggest throwing money at the situation, but the problems are not due to lack of money. Even properly describing the problems is awkward, getting into things that are awkward to discuss.

Here's the main premise: "Even the most thoughtful and well-intentioned school-reform program can’t improve educational outcomes if it ignores the single greatest driver of student achievement: household income."

I generally agree with this. High-quality education starts not with teachers, but with parents. And parents can't do their part if they don't have stable income and enough free time to... actually raise their kids. This then gets compounded by wealthier families being able to afford the more expensive housing that comes with better school districts (or opt out of public school entirely and pay for private school). Then it compounds further with wealthier families being able to afford tuition instead of saddling their kids with mountains of debt. It ends up being something of a vicious cycle.

If most of the returns are to capital, may the issue is simply that most of the people are stuck with wages and not capital.