This divide began when Rush Limbaugh became popular. He really was the start of all of this...the mocking of political opponents, the blatant racism, the sexism. All broadcast during the day to people who could do their jobs while listening to the radio (working class and blue collar workers primarily).
Limbaugh primed the pump. Democrats are to blame for just assuming they had the blue collar vote, and they didn't do anything to help cultivate that vote. Got a little too uppity there for a while, valuing college education above just about everything else, leaving those who didn't want to go to college feeling left out and demeaned.
Enter Trump, who, despite what the common mantra is, is not JUST a symptom. There are things on both sides of the aisle that allowed for Trump's overt racism to capture the hearts of a lot of Americans, but Trump IS the cancer. He is uniquely a bad person, a stupid person, a criminal, a narcissistic psychopath; a combination of qualities that no other Republican leader posesses (though some have many). He was in a unique position to gain the following he has...a SEEMINGLY successfull businessman (scoff) who ran in 2016 by saying he didn't need anyone's money to run...that was refreshing, and even I was impressed at the time by that (soon learning that he was all smoke and mirrors with regard to his wealth). Trump caught lightning in a bottle by running against Hillary Clinton, who, was not well liked, and Americans have proven to not yet be ready to vote for a woman for President.
Democrat leaders haven't done themselves any favors by embracing transgender females being allowed to participate in girls'/women's sports or by supporting medical gender care for minors. Most Democrats do NOT support those positions, and I do believe that over time those things will not be allowed.
There will not be and can not be any movement to the norm until Trump is out of office finally. He tried to overturn a fair election. Democrats and people of sane mind will always be against that.