They are the only states with two SEC members. Alabama has a population of 4,661,900 with Alabama and Auburn, both who recruit nationally. Troy and UAB are the only other Division 1A schools, although USA plans one. Tennessee recruits nationally and always has, as does, Vanderbilt. Tennessee for recruits who are great athletes, Vandy for good athletes who can get into their school. Tennessee has a population of 6,214, 888 and 3 Division 1A universities. Mississippi has a population of 2,938,618. Mississippi also has 3 schools who try to compete in Division 1A.
Here are the SEC schools with their state populations:
Alabama and Auburn: Population 4,661,900, about 2,330,000 population per SEC member.
Arkansas: Population 2,855,390, 2,833,390 per SEC member.
Georgia: Population 9,685,744, 9,685,744 per SEC member.
Florida: Population 18,328,340, 18,328,340 per SEC member.
Kentucky: Population 4,269,245, 4,269,245 per SEC member.
Louisiana: Population 4,410, 796, 4,410,796 per SEC member.
Mississippi State and Mississippi: Population 2,938,216, about 1,465,000 per SEC member.
South Carolina: Population 4,479,800, 4,479,800 per SEC member.
Vanderbilt and Tennessee: Population 6,214,888, about 3,107,000 per SEC member.
You ask why MSU struggles to compete in the SEC? Lowest budget, lowest population support, and highest competion for recruits. While true that Georgia also has Georgia Tech, Florida has FSU, Miami, USF, UCF, and FIU, they are still not in the SEC. Louisiana State competes against La Tech and the directional schools. Kentucky competes against Louisville, and Arkansas competes against Arkansas State.