The tautology is in only looking at the subset of spending that's done through incentives, and then complaining that it disproportionately goes to people buying expensive stuff. That's what incentive means in this context: incentive to buy expensive stuff.

Anyway, you're coming at this all wrong. If I was in charge of designing this program, my mandate would not be to help poor people or rich people, it would be to increase solar power. How do you increase solar power? By paying for part of it. Who benefits? Whoever's buying it. Who pays to install solar power? Not poor people.