The actual old Tidewater Virginia and Coastal South Carolina accents were more or less lost, or so I’ve been told. After the Civil War, Southerners wanted to sound as different as possible from Northerners, so they adopted the back country accent that has come down to us as the “Southern accent.” Perhaps some people cling to the old ways, but it’s similar to upper class Boston or New York or Philadelphia accents which aren’t much heard in the real world.
I dunno if it was so much “wanting to sound different”. The Tidewater accent was very much an upper class kind of thing. You didn’t hear it much from yeoman farmers or the like. As for the Coastal Carolina accent, there were always so few speakers with this accent which arose due to their relative isolation. In more recent times more contact has watered it down considerably and it will soon be blended away.
I can hear the difference between Texas, Louisiana, Appalachia and the “standard” Southern accent. Maybe you can hear an especially strong “Tennessee twang” (listen to Steve Spurrier some time) with a few people but generally the standard Southern accent prevails from Central Florida up through Mizzourah.