Maybe the New Orleans suburbs were more populous? Contrary to the popular meme of the old Dixiecrats becoming Republicans, most GOP gains came from the "New South." Reagan probably lost a majority of Deep South counties but carried every state except GA.
Keep in mind that John Anderson's candidacy in the 1980 Election might have took enough votes away from Jimmy Carter to flip Arkansas, Mississippi, Tennessee, North Carolina, South Carolina and Kentucky to Ronald Reagan (albeit by very slim margins). Had John Anderson decided not to run in 1980, Jimmy Carter would have had a very good shot at carrying all six of those states.
