Bookmarking this one, I must write a hub :D. Short answer -- I come from the severe end of poverty. As in, we live in Wyoming and had no heat, we'd sometimes go for days without food, our house was an old trailer that no longer had any insulation, etc. My sister and I were raised with a full awareness of how harsh life can be. It was constantly pounded into our heads that if you can't earn it, you don't deserve it. People are not out there to help you, they're out there to see how they can take advantage of you. Nothing is more important than getting your bills paid and food on the table.
Sadly, in a very depressed area, that meant that my parents worked themselves nearly to death, refused government assistance, and still couldn't gain any traction. It meant that money was the constant "elephant in the room," and they were always stressed and trying to find ways to fit more work into the day. When we played, it was just my sister and I, and it was just to keep us out of the way. Whenever possible, we worked. That's just what you're expected to do.
For people who are better-off financially, the entire "messaging" of childhood is different. The importance is on education, bettering yourself, finding productive ways to be valuable to the world -- even being happy. These things are totally foreign to someone who doesn't know where his or her next meal is coming from.
In short -- it's not that money-poor parents care less, or love less, it's that they're constantly in survival mode. They think that by imparting the world's harshness to their kids, they're helping their kids survive. If you already know you have a good home, food, clothes, etc., then mere survival doesn't even seem to come into play and quality of life can take on a greater importance. This is the fundamental difference in thinking that I bear in mind while raising my kids, because it is a huge factor in keeping the poverty cycle going, or in finally breaking it.