Yeah, it's definitely changing. And just as always, its really a result of a few careless bad apples ruining it for everyone else. You have no idea how much it bothers me to find areas out in the MIDDLE OF NOWHERE where someone just decided to dump a bag of trash or leave a pile of beer bottles. There is just no excuse for it and it is those people who eff it up for everyone else. Not to mention all the folks who cut new trails in there "thrill craft" and get all the environmentalist fired up.
The truth of the matter is, it doesn't matter how much you try, you still have a negative impact simply by being a living breathing human. So like you said, enjoy it while you can...
Bart