The Redneck left lasted for a while. The Dixiecrats and so forth. Adalai Stevenson and finally JFK and LBJ drove them away.
Adlai Stevenson didn't drive them away (though Ike managed to get more support in the South than previous Republican candidates). All the states Stevenson carried were in the Deep South, and both his running mates were Southern Democrats (one Deep South, one Upper South). At any rate, the "solid South" was still in play in '52 and '56, and I don't recall any "principled" Democrats decrying this "southern strategy."
Conservatives often forget that the Solid South was one of the original members of the New Deal coalition. Despite modern revisionist histories in which FDR was opposed by a South full of "rightwing Republicans" and personally liberating Blacks from slavery for a second time, FDR was always a hero to Southern whites (TVA, anyone?).