I suspect that some of the downturn in attendance has to do with perceptions of how dangerous the parks can be. It is like what happened to beach attendance when the movie "Jaws" came out. The parks and wilderness areas just don't make the news unless someone gets lunched on by a cougar or bear.

Some time back I told a friend I was going out to a nearby wilderness area and he asked if I had a gun. I said I own one but didn't bring it. He tried to get me to take the shotgun he had in his truck. He meant well but the impression he got from the news was that the woods were dangerous with people getting attacked by wild animals all the time. I tried to explain that odds are I was far safer in the woods than I was in town.