I know it's a circular argument - but because if they (or their parents) could manage resources better they wouldn't be poor - don't look at what signle person does - look at their bloodline.
My parents (mother mostly) managed to save enough money to buy her first property by age 18 (she started working age 15). She managed to save incredible amounts of money - while mostly working minimum wage type jobs - for her entire life and we always had cash when necessary.
It did take a lot of sacrifices. I mostly wore second hand clothing until I could afford to buy my own. I was never to McDonalds until age 15. We never went to theatres. We spent most of our vacations working, She did a lot of stuff that is nowadays considered ecological/organic/fancy - but 30 years ago made you look like a lunatic in eyes of general community (recycling/reusing everything - like taking zippers off clothing and using it on other clothing). I was raised entirely on organic food - thinking that I'm deprived because of it. But I was always encouraged to study - hell I was probably second kid in class to get access to a computer and certainly first kid in class to have their OWN computer.
Hell I might go and write a "How to survive on 100 dollars a month." guides only on stuff I learned from her.
I was certain that we are piss poor until I realized that we are actually pretty wealthy - just poor on liquid assets.
Bootstrapping yourself from poverty is certainly possible - but most people are just too ignorant (yes it might be cruel but thats the way I see it) to pull it off.
Have you ever noticed how many poor people smoke/drink - have you ever considered what a % of their income goes towards these habbits?