https://www.youtube.com/watch?v=lHdXQAQHjd8
People who could appreciate this message from first hand experience died off.
By 1990, they would have been 60 or above, with the median probably in the mid 70's. By 2010 they were mostly gone.
Prior to the 1950's everyone who could vote, voted Democratic in the South save for a few enclaves. Beginning in the 1950's Republicans began to win over middle class voters in metropolitan areas, once the Bilbo generation was no longer around to chide them at Christmas Dinner over the fact that Bill Sherman burnt daddy's barn to the ground and killed Uncle Johnny at Chattanooga. A large number Midwestern and Northeastern people of similar class moved to places like Tampa, Charlotte and Dallas as well. Together, this created the suburban base for the GOP in the South that became its backbone for decades. This was evident in 1952 and the voting power of these places grew over the next 40 years. Civil Rights issues like busing were of major concern but it is hard to claim they flipped just because of Civil Rights. At best, it just padded the margins among this group.
Rural and Working Class members of that same generation, though (GI and Silent largely) were helped by the New Deal and therefore remained Democratic but for different reasons then their parents and grandparents (Civil War Legacy voting). This allowed for the rise of the New Democrat in the 1970's and 1980's, like Terry Sanford, Jimmy Carter and Bill Clinton.
Their children and grandchildren though were alienated yes by the Civil Rights issue as well as the general social issues that motivated Boomer voters and late Silent voters all across the country. Thus the rise of God, Guns and Gays (as well as life) becoming strong motivations that finally tipped many rural districts in the 1994 elections, in conjunction with the Supreme Court requiring a higher concentration of African Americans in districts. This ruling thwarted Democratic Gerrymanders in GA and other places built around spreading out the African American vote to prop up White Democrats who needed that 30% or so to get close enough so their aging Yellow Dog support was enough to win.
By 2000, FDR seniors were largely being replaced by Ike seniors (President they came of age with). This is considered to be why Gore fell flat with Seniors compared to the numbers he was expecting to obtain with the Lock box messaging.
This is a great answer. I'd add that the 1990 SCoTUS VRA district mandate was the death blow. Alabama and Georgia are case in point
