The class A resorts I visit here in SC are more like condo's than campgrounds. Each lot is individually owned and the management rents them out for the owners when they are not occupying them. They have association fees etc. just like a condo association does. Each site is individually "upgraded" by the owner with outdoor kitchens, cobblestone drives etc. I don't believe these resorts are money makers, but more offset the cost type of thing. I believe the owners only want the upper echelon as clients.
I must admit, I feel like Sanford and Son driving into the sites and being next to 1 Mil. plus Prevosts :)
Lets face it, $60/night in one of the most sought after areas on Hilton Head is a steal no matter how you look at it.