Camping isn't the only hobby, golf, fishing, canoeing, back packing, biking, hunting, skiing, snowshoeing, trap shooting, etc... all seem to be dwindling. When I was in a fishing league we had a "take a kid fishing" day (big boats, some members were guides even.) When I was a kid I would have died to have had that type of opportunity, now there were more boats then kids.
I have no idea of the real cause, but I think fast food and the digital age has a big part in it. As far as wealth is concern, most have high bandwidth internet for gaming, $100/month cell phone plans, and paid TV of 100 channels or more, and fast foreign import cars. Can't imagine that money is a "need" vs a "want."