Horry County isn't the only part of the state that is growing. There is still Charleston, Greenville, and the Charlotte suburbs that provide opportunities for the Democrat.
Compare that to a state like MS with stagnant growth and arguably one of the worst brain drain rates in the country. MS black population has been moving only one point every decade. It will take a long for demographics in MS to get to the point Democrats need it to be.
Are the Charlotte and Charleston suburbs liberal transplants or more rural conservatives who relocated there for the jobs? I remember hearing there were liberal transplants in Charleston suburbs but I don’t know. I would think the conservative whites would go up to Greenville County for all the manufacturing jobs. Can anybody elaborate?