Growing up, my family was at the lower end of middle class, a couple steps up from being really poor. So I have always been strongly motivated to study hard, get a good job & have a good amount of cash. Partly because of that, I have historically believed that if you are focused then you can pull yourself up by your bootstraps. Not having lots of money doesn't prevent you from going to the library. You can take advantage of what the public schools teach you, provided you study hard. Loans and scholarships are available for college if you work for them. Don't get distracted by parties, games, TV, etc. while in school & you should be just fine.
That was how I felt until my senior year in college. That fall I participated in a mentoring program at a local elementary school. I was paired up with a 4th grade boy, David, who needed help with math. So once a week I would go to the school and we'd go through his math work for an hour or so after classes were over. Once or twice we just hung out and threw a baseball outside as well.
What did this have to do with why did my opinions change? I guess I just started realizing how being poor can handicap a kid. When I was working with David I realized that things my mom had helped me learn when I was his age, he hadn't had that option - his mom had to work a lot since his parents had been divorced. When I was a kid my parents had bought a set of children's encyclopedias (published by the Worldbook people), and I always had ready access to reading those at any time of the day. The library is only open at limited times, and when you're a kid you can't just hop in a car & drive there. Also, he was often hungry. I remember bringing snacks once to a study session - I had skipped lunch to study for a test - and he wolfed down the food in a heartbeat. It's kind of hard to focus on learning things when you're hungry.
Years later, I would think even more about David. He lived in a rural area, where the schools just weren't very good. The library was in the middle of town, so he couldn't get to it easily. He didn't have a lot of time to do school work after hours because he had a lot of chores. Then I related that to my dad. I'm pretty sure that if he had been born into a different part of the country, & his family had more money then he would've been an engineer of some sort. But he grew up in the woods of Kentucky, quit school when he was in 8th grade because he had to get a job, & bounced around from one factory job to another. Sure, he managed to become an electrician, but that came at great effort and not until he was well in his 30s.
There are other ways that being poor can make it tough. There is a strong link between nutrition and brain development. If a child doesn't get good food, his brain as well as the rest of his body suffer. If a child has to work a lot to help make ends meet, that means she can't spend time learning things she'll need to make her own life better as an adult. If you live in a geographical area that is dirt poor, then the public amenities like schools, libraries, etc. are probably either scant or nonexistent.
I think the point I'm trying to make is if your family is poor then sometimes there aren't any bootstraps worth pulling.