Will the deplorables vote for a black person, no matter his political positions? Many fake Democrats voted for Bernard because of his white maleness over Hillary Clinton, who just happened to be a accomplished women. The whiteness of states like Wisconsin and Iowa will help Bernard secure a victory, as much as it pains me to say.
If you care about the health and growth of the Democratic Party, then you probably shouldn't make such sweeping judgments against its future considering Bernie won young people of all demographics, including young women and young Black people.
You would consider Democrats in West Virginia and Oklahoma to be representative of the party? Those were states that went heavily for Bernie, both majority white and conservative states. The Bernie coalition is going to collapse as his people just happened to be the people who were radicals in college only to be Republican when they start playing taxes.