Give it time - the junior/amateur leagues run deep here and have grown to be the largest in the country. They're getting even bigger.
Aside from organic growth, you need a generation of existence for a professional team to produce embedded fans. In other words, kids have to grow up rooting for and aspiring to be, or at least trying to be, their idols on local TV. Good examples of this are Gavin Brindley, Ryan Carpenter, Ryan Hartman, and Michael Kesselring. Joe Snively is probably the best example because he grew up rooting for the team that eventually drafted him.
It's worth noting that there are A LOT of players in the FPHL/SPHL/ECHL that are from Georgia, Florida, North and South Carolina, and Tennessee. Give it 5-10 more years (time) and I bet you start seeing more and more NHL players that are either from the south or grew up in the south. Kids down here don't have the amenities and coaching that they do in Canada but they're making progress, they just need a bit more time to start closing that gap a bit more.