The influence of movies and national TV has had an influence on kids growing up in the south. Mainly kids shows on TV. So the local southern drawl may be going away a bit. But not so much in the deeper, smaller rural areas of the U.S.. Local news people, in the South, may not actually be from that area but other parts of the county. Tend to move from broadcasting jobs, trying to get into a bigger market(CNN, Fox news, etc.). If going to broadcasting school, on the job radio training, etc you will usually be taught to develop and use a radio or TV voice. Get this example a lot from DJ's on the radio.
Got back from eastern Oklahoma a couple of months ago and still local accent or drawl from most people. Southern Indiana has it's own accent, as does the Boston area. But another generation or so, maybe the speech pattern will be the same. Hope not, pretty attractive on Southern girls.
Side Bar: Actually the south has some very outstanding colleges, though people tend to be bias from their Southern drawl. Also famous writer from down there.
