Sorry, I wasn't denying that Texas spends more money per capita on textbooks. As you point out, it certainly does, according to the article.

I was worried that someone might read that Texas's per-capita spending is higher than California's and draw the conclusion that this is a big reason for why California's schools suck. I've heard a lot of people make arguments like that. "Small Country X spends so much more per capita on Y! (Implied: That must be why Y sucks for us, and our lives would be better if our country would spend more on it.)"

So I gave one reason why the returns California and Texas get from their respective textbook purchases are probably not proportional to their per-capita budgets.