The voter trade thing is spot on. And the GOP was the minority party when it was made up of what we used to call the "green eye shade' class - i.e. a lot of well educated and/or small business professionals. But I will theorize a difference for you, which is that in prior generations the working class Democratic voter was much more tuned into democratic process. He may have been an a vet that had to go to war against fascism, or an immigrant that fled empire or totalitarianism, or belonged to a Union or VFW or American Legion or a democratically run Protestant Church, or some other civic org that maybe ran Roberts Rules of order in some internal rules based democratic process that gave them a basic appreciation of democratic management, truth based politics and rules based procedure that prevented prior generations of working class voters from seeing any appeal in a national political politics that has gone off the rails toward deceit and what is basically fascism, the way this GOP has.