My own experience supports this claim. While I didn't grow up poor, my middle-class parents separated the week I started my freshman year of college. What money there was went to lawyers instead of college tuition. Realizing I was on my own, I took two jobs and tried to make passing grades (mostly succeeding), but after a year I was forced to face financial reality. Already in a lot of debt, I dropped out and never went back.

So when it comes to "who gets to graduate," I have little doubt that financial and emotional support are more important than academic ability.