I think it’s complex.
I think parental attitudes to education and employment/careers, as well as parental aspiration for their children has a big impact on children and their educational outcomes. Some children are born with drive and ambition, and will succeed whatever their parents attitude or whatever peer pressure the come up against. Other children need encouragement and to be given confidence that they can succeed should aspire to a career outside the norm for their family/peer group- without it, they won’t have the confidence to step out of the “comfort zone”.
Many children, especially teens, like to conform to the norms for their peer group. If you have a peer group who expect to have to do well, expect to go in to higher education and so on, then you are more likely to have those expectations too. If everyone you know is mainly at school because they have to be, expect to leave and get a local job in whatever is available, then it’s more likely that that will be what you will be aiming at too. Not inevitable, but more likely.
My father came from a very low income area- his parents grafted in hard, physical jobs their entire lives and scraped by for the most part- they had little time to devote to helping him with his school work (if they had even known how- both left school at 14) or thinking about a career. A career was something outside their experience and although they obviously aware that some people did this (they knew about Dr’s, solicitors, teachers etc), it wasn’t something they would even have thought to encourage as he was expected to leave school and get a job. Like they had done and just as everyone else they knew had done.
There was also no way they could have afforded to send him to university, even with the grant system. Added to that, when he met my mum and was encouraged (and funded) by her to go to night school and then university, there were lots of comments about “getting above himself” and “why was he wasting time, bothering with all that”. He was told he was “going soft” or “become a snob” or “you’ll be thinking you’re better than us soon”- and many other jokes/digs/criticisms. That might have been enough to discourage some people from starting or continuing, especially a teenager (my dad wasn’t, he was 20), as they often do almost anything to conform to the social norms of their peers.
Times have changed, in many ways, but there are still parents don’t encourage their children because it doesn’t occur to them that they can or should, because they don’t know how to help as they have no experience of further or higher education, or how to go about starting a career. They might ‘encourage” their children (which has value, of course) but without anything to back up that encouragement it’s a bit vague.
For some, sadly, they actively do not want their child to do these things- they don’t view education as valuable/think it’s a waste of time or don’t want their children to leave them behind (maybe they fear losing touch/having less in common with their children) or become “one of them”/“a snob” etc. My friend works in a school in a very deprived area and she comes across those attitudes more often than I’d thought.
Add in that if you don’t know certain career or profession exists how can you aspire to it? My DC know people who have wide and varied careers because of the careers of relatives, our friends, their friends parents, even friends of grandparents and so on. For instance- they personally know adults who work in: farming & agriculture; medical and a number of associated professions; vets: engineers (several different fields); solicitors/lawyers specialising in a variety of areas; people who work in banking and investing/acquisitions; rural estate management; owners of small/medium businesses; senior management; CEO of a major international firm; academics in the sciences, language and social sciences; forensic archeologist; climate/ glacial geologists; senior civil service; several who work in bodies like the UN; a master saddler; master farrier; theatre production; musician in a national orchestra. If you are exposed to these different possibilities- and the knowledge that there are many more possibilities out there- you are more likely to find your niche/something which sparks an interest or fires the imagination.