That notion has been turned on its head this election. Following is a graph of the percentage of Hillary voters per income. You will notice that the very top one of 93% is DC. Is it any wonder that they have no clue why Trump won? They are insulated from the working class.
They've abandoned the working class and haven't delivered for the poor. Democratic voters live in gated communities. They don't see the shifts and friction of culture. They are just upset that they lost their gardner
Just to be clear, how are Trump and the Repubs for the working class when they are going to drive up costs for 90% of them? Or do you think the working class works entirely in manufacturing?
White, blue-collar males - and females - without college degrees were once solid and stolid Democrats at a time when they had effective unions to defend them against corporate exploitation. If they feel abandoned by the Democratic Party, they have just cause. The highly-paid manufacturing jobs that have been lost to technological efficiencies and the capitalistic allure of low cost labour elsewhere are not about to be resurrected. Whether Trump can do much to ease their plight will soon be seen. Good luck.
Identity Politics lost it for Hillary and the Dems. White people and males who would be benefited by Dem policy have rightfully decided that its not worth getting on their knees and begging forgiveness for things they didn't do from minorities, women and LGBT to get it. Dems will lose until they drop PC and identity politics.