I think that to conflate "true leftists" with "cultural elites" is kind of silly. When I think of the stereotype of a New York Times reader from an upper middle class suburb I don't think liberal do much as a fiscal moderate+social liberal who would in an earlier generation have been a Rockefeller Republican. On a lot of issues like expanding social security, raising the minimum wage etc I think that if you asked a lot of people they'd probably lean left on all of them, it's just that liberal has a negative cultural connotation. I bet that on fiscal issues plenty of working class white people are to the left of the suburban yuppie/whole foods stereotype.
Yes, thank you. So-called coastal elites are socially liberal but are not "left-wing." In the UK, many of these people would vote Tory and in Canada their party of choice would be the centrist Liberal Party not the social democratic NDP.
Keep in mind that the very elite sections of the Upper East Side did not vote for De Blasio.