Honestly? Depends how smart the young adult is (academic and focus/ life skills)
if someone has a good English degree from a top university and is working in a bookshops that’s entirely on them.
Corporate graduate schemes are open to pretty much all subjects providing they demonstrate academic ability and hard work. I work with plenty of big 4 grads who have degrees in English bio chemistry history etc… they rely on certain universities to select the best then rely on their own recruitment criteria to get to the highly trainable ones.
the stats play out how successful for both the students life and generational wealth any degree is (at population level) particularly for those from low income backgrounds. As others have said it’s about maturity, diversity, forming relationships and being exposed to people and information- effectively making better jobs accessible.
for you making better jobs accessible might mean being a doctor or lawyers but for many, many students that might mean a job at a local authority or similar institution with an excellent pension and steady wage to qualify for a mortgage. And these situation particularly are were post 92 unis have excellent track records.
this conversation is often dominated by Micky mouse degrees and people who can’t understand how important education is for getting people out of poverty, but that’s your own ignorance speaking.