Older courses like Gator Hole and Bay Tree are being developed. But the high end courses are safe for a long time - especially given the slump in real estate. What you describe is one of the reasons I prefer the south end of the grand strand. I can play True Blue, Caledonia, Heritage, Pawleys Plantation, Willbrook Plantation, River Club and Litchfield without the hassle of Myrtle Beach proper - unless I want to go to Martin's that is.
