There are a few things at play...
We look at challenges with modern day eyes whilst at the same time the more current drive that all careers start with a university degree limits others.
My mum is severely dyslexic but was only diagnosed at 14 and left school 6 months later. She got no support, it was just an explanation - you can barely read because you are dyslexic it was always going to be this way. Now she would have picked up much earlier, had greater support and would have been channeled into subjects that she excels at. As it was she spent 35 years as an untrained nurse. She is caring and with the right support could have managed to become a qualified nurse through the old route of on the job training but probably wouldn't have managed to qualify through the university route.
There is a mismatch in salary and worth. There are the 5 C's which are jobs mostly done by women which have been historically considered as less valued and this ae These are caring, clerical, cleaning, cashier and catering.
Often in communities this isn't a single person problem but a family and society problem. If you are living on minimum wage and have a family it is less likely that you can support other members of your family through education to get the bits of paper that permits them to do the jobs that can get them out of the minimum wage trap. So we have children stuck in low waged jobs because that was all there grandparents could manage and because of that their parents had to go straight into the workplace to bring in money and that means they don't have the funds to support their children through further education.
Money breeds money, channel 4 a few years ago did an experiment where they have two shoppers identical Christmas lists. One was from a low income household and the other a higher income household. Guess what the low income household had to pay a lot more for the exact same times. Primarily as they couldn't afford to walk into shops and buy them outright. When you are living like this you need to work more hours to cover your costs and you have less time to retrain and you have a large emotional burden of life which reduces the headspace to look for alternatives. Furthermore, without a built in safety net should the new career go wrong it is harder to make that jump.
I have been fortunate, I've benefitted from a steady increase on fortunes from generation to generation. My great grandparents on both sides were living on the breadline trying to stay out of the poor house poor. My grandparents on both sides were low waged but benefited from the welfare state which moved the families into "working class". My dad managed to get on an apprenticeship that was great for him, he has an innate gift for logic and as it happened the trade he was assigned at college fitted this and it got into allowed him to move from working in the trades to being a highly skilled trades person moving up the ranks within industry. My success right now is heavily linked to this. This allowed the family to jump from "working" to "middle class". My parents were able to support me and my sisters through our a levels and on to further education. This has given us all the ability to earn more and with that we have all built comfortable lives for ourselves. It took me 11 years, 2 degrees, and 2 1 year training posts to qualify. This nearly doubled my starting salary but it was a luxury I had because I had parental support.
Careers advice is also pretty poor, it often lacks imagination. The decision of what courses and careers is often linked to a subject you mostly liked at school there are so many interesting and well paid careers that many kids haven't heard of. My cousin did psychology and a few weeks into her degree realised it was a mistake, she got a work experience through a family member in construction and she switched to a degree linked to surveying and loved it.
This neatly brings me on to my final point and that is so often it is not what you know but who you know. I got a summer job because my sister worked there and I knew they needed a short term hirer to cover annual leave. This gave me 6 weeks experience in a lab environment at the very bottom of the ladder. This allowed me to talk confidently about working in a lab when it came to getting an industrial placement also the first comment from one of the interviewers was "I worked their too, small world". From getting that placement I was able to get funding for my PhD and once I graduated allowed me to get a role in a similar company as I had done part of the job already. I got all of these positions from my hard work and abilities but I still note and value that 6 weeks job at 18 as being very influential too. It gave me something in common with the interviews, it showed I had some real life experience, something different to other candidates to talk about in interviews and generally meant I started interviews on the front foot when I could then talk about my skills and abilities.