Train great posts.
My curiosity stems in part from finding ourselves, public sector workers, living equidistant from what at the time were arguably the best and worst schools on the country with few other options for heathen, non 11+ passing children. We opted to pay, rather than commute, and in the event the Council were unable to find a place for my son anyway.
As a result I effectively worked two jobs and the children were used to see parents work hard and prioritise their education. Other parents, the sucessful ones you describe, will also work extremely hard, and expect their DC to do the same, have sky high aspirations, with them all treating education, the broader stuff not just grades, as a top priority. At school they received, from great, dedicated but normal teachers a lot about education being a privilege and a responsibility.
DS adapted quickly to a course largely populated by overseas students. His gf is now in her home country and gets three days leave a year. He and his friends seem to assume it is normal to do the same at University. DD in contrast, in a more traditional university but a sought after course, has been surprised at how some of her friends lack study skills. They think they are working hard, and indeed may spend all weekend studying for a test, so are baffled about how DD seems to fit a lot of other things in yet still get the required marks. DD does not understand either. Her friends at Oxbridge manage similar feats. (One is studying Chinese for fun but others manage high level sport, music etc alongside their degrees) It appears DD has learnt to work smart as much as work hard. Training, aspiration, expectation?
I make no particular boast for the raw material, but DCs schooling has developed their abilities and ambitions and appears to have them prepared to make the most of University.
Do you deny cancer treatment to some, because it is not affordable to everyone? Would you forgo a family holiday to pay for important cancer drugs not available on the NHS?