Going against the grain here, even though I'm well educated, middle class, nice house in nice area, no mortgage, languages, music blah blah blah. The factors for people of my kids' generation are going to be:
Access to affordable property / inheritance
Trades - the people with the most cash these days, and choosing their working hours, are electricians, plumbers etc. DH and his 2 siblings were privately educated on FIL's wages as a white collar professional -MIL a SAHM. They wouldn't be able to afford the fees for one child these days let alone three. They wouldn't be able to afford half their property, either. The only people I know who can afford private fees are NHS consultants or property developers that made their money before their recession.
Excellent up to date IT skills
Social and professional contacts, via family / school / friends
Not being a dick and being able to work with others
Good health - which in this country is very linked to your social and financial situation unfortunately
But basically without access to cash or property, relying on a good education, the gloss of university and a desirable accent is just not enough.