I don't think that anyone is saying it is generally impossible; just that there are a lot of variables in how successful one can be in "pulling oneself up" through sheer hard work.
What isn't reality is believing that what worked for you will work for everyone.
You know, when I was a young woman just out of school, I did believe that it was just that simple. I grew up pretty hardscrabble, though because we were in the country in a warm climate and we hunted, fished, and grew veggies, hunger was one want we didn't have to worry about. My dad worked at a skilled trade, and my mother stayed home with we kids. (That wasn't as devoted as it might seem; when you live in the sticks and have proved yourself incapable of learning to drive, your options are limited. Mom quite frankly stank at dealing with children, but since she could not drive and there was no public transportation, getting a job while we were in school was not an option. She took on sewing projects at home, but that was the best she could do.)
My father died when I was 12, and our standard of living immediately fell to about half of what it was before. We lived on a survivor's pension. I worked hard in a crappy impoverished school district, diligently studied how to win at the scholarship game, and got myself through college. I did it, and l was pretty darned insufferable about how if I could do it, so could anyone else. Fast forward about 6 years: in a new job, I was assigned to learn a process that involved some pretty complicated math, and no matter how hard I tried, I could not learn to do it without making mistakes that had to be corrected. I just could not get it down solid. My trainer lost her temper and said, "How can you not get this? It's easy stuff." And then it hit me: she could do it, and therefore I must be lazy if I could not do it, too. But I wasn't lazy; I was working my butt off, and my brain just would not cooperate. That's when I started to look with new eyes at the people I had left behind in the world that I grew up in. The truth is this: much as we may wish it otherwise, hard work alone is not the key to "rising above your raisin'"; you have to have a certain measure of luck to go along with it. Hit the bad luck jackpot and your hard work won't count for nearly as much as it otherwise might have. I worked danged hard, yes, but I also got lucky in a lot of ways. I had some teachers who encouraged me, I had enough intelligence and patience to do well in school, and I was reasonably attractive, which undoubtedly made the difference sometimes when I was bluffing my way through a job interview. Here's another one: when my father was dying of lung cancer, even though it was occupational, he made me promise never to smoke. (Poor Daddy. He gave me a leg up (and saved me a fortune) with that one.)
There is a book that I like a lot, called Heartland, by Sarah Smarsh. She's a journalist; a graduate of the University of Kansas J School. Before that, she grew up on a farm, and she comes from a long line of impoverished women. Early in the book, she makes this comment:
