I can relate to you on this one! While out Christmas shopping recently, two separate cashiers at different stores complained to me about their lives, without me asking! After each complained, I asked where they graduated from & what they were trying to do to change their circumstances. Each said they graduated from area high schools and then irritated, acted as if high school is enough. Sorry, in today's world you need a trade, a successful entrepreneurial bent, and/or a college degree to be comfortable financially and otherwise.
There are a variety of reasons however, it often comes down to a person's mindset/choices, their opportunities (or lack thereof), and their familiarity and preference for what is known versus what is not. Time and again, many choose to be a fraction of who they could only because less than is familiar to them. There are some who have opportunities to better themselves and/or their financial situation, but to please others or be "accepted" by others (who may not even be good people/role models) they don't strive for better. It is truly sad knowing that adults actually act this way often to their detriment, their families' detriment and that of their communities.
Others may have an opportunity, several or even many to better themselves and their financial situation but will choose not to due to a lack of confidence, a lack of hope, or flat out fear of failure. Perhaps those frozen by any of these things don't know that inaction where action is needed is also failure?
Perhaps their choices are due to immaturity, stupidity, lack of money, laziness, or are complicated by other choices they made previously which make it very hard to gain or grasp any opportunity. A common example of complicating future opportunity is when one begins having children they cannot afford. Other examples of harming one's future and opportunities include not finishing high school, not going to college or learning an in demand trade, or becoming a criminal.
Some people of all races come from long lines of the traits in the above paragraph. What I've personally seen is even excellent mentors not being able to break through even with copious investments of effort with some like those you describe. Even the mentor's encouragement, experience and resources could not outweigh the negation of who and what their mentee chooses to be around or with. If one's family and or friends have a disdain for improvement, for too many, they will very likely also be ensnared.