I think this is a bit out of touch. People in the situation you're describing are generally coming from a place of desperation, not of careful contemplation. And yes, it would behoove them to plan meals and pinch pennies, but when you and your spouse are working 50+ hours a week each to make ends meet, the type of self-reflection it takes to make those decisions is in very limited supply.

I've not been in a working-poor situation since my late teens, but I can say that there are times when I was working 60+ hours a week, and I did not have any energy to think about meal planning or healthy eating or investing in my future besides dumping some extra money in a savings account. Luckily, I did have the money to eat healthy, and luckily my wife was (sometimes) in a position where she could meal plan for the both of us, but oh man...if I was in the same situation and making < $30K/year, I would NOT have been able to even think of these things.

It's not about being intelligent or even about resource management, it's about having the energy to think about it, and if you're working your fingers to the bone, you don't have the energy. So it's easy for us to sit around on a forum while there's a lull in our cushy jobs ranting about how poor people should manage their time better, but I can tell you that it's not easy.