Interesting question to me as i've been researching the long standing historical near social 'apartheid' of this country (clearly under some strain from mass university education and soft-proleratianistion of many of the traditionally m/c jobs - sorry, professions). the classic case as put by E.P Thompson was that the new working class in this country in the late 18th/early 19th century moved to the city and apart from working for them had little or no social interaction with those 'above them' they formed almost separate species unlike in say france where there was, due to the slow pace of urbanisation and lots of families actually owning the land they worked and a social mix was the norm. The only really comparable place was Germany pre-ww1. Here, all living in the same places, working at the same places, drinking in the same pubs, following the same team etc developed a gap that only individuals could or would want to cross - rather than large groups of people as a whole (that didn't really happen to any extent until the effects of the post-war rebuilding kicked in in the late 50s/early 60s).
The upshot, for this thread being, that there remains a stubborn residue of them lot over they're they're different, they don't have the same interests as me/us and that is not going away anytime soon, based as the original ideas/feelings were in a long lasting and life-shaping material circumstances. And, it should go without saying, that this also impacted (and will still do) on the way traditional m/c also view the trad w/c and how their interests intersect/compete etc with that of what they see as theirs.