The old left wing disappeared with the implementation of neoliberalism. All the workers wanted to be rich all of a sudden, so they gave up their workers identity and all decided to live their dreams and pursue becoming rich. Or enough of them to vote that policy out of existence.

The reason the DNC keeps nominating people like Biden is because they won't change the economic system back to a mixed economy. All the other candidates essentially wanted the welfare state (which is the outcome of a mixed economy - part socialist, part capitalist).

The old way of classifying left and right has departed the room.