"classism."
You don't have to look hard to see upwardly mobile, right-thinking "progressives" looking down upon poor people. When Hillary spoke of "deplorables," do you think she was thinking of wealthy businessmen who support Trump? She had some others in mind and her comment isn't one that is uncommon within her party, despite the rhetoric.
A century ago, the base of the party was union workers and rural farmers. Now the influential base is increasingly an urban, upwardly mobile class. It was probably inevitable that this all would happen.