Steve, I don't want to keep anyone out of the backcountry. It is always a delight to meet newbies on the trail, and see the wonder in their eyes.
Never assume you know what is going through an old man's mind! What the young achieve through energy and brute force, the old achieve through steath and deception...LOL.
I agree with most of your suggestions (surprise, surprise), but still believe numbers ought to be cut back. Whew, finally we might be getting somewhere.
Maybe what is needed is a few S&^$% inspectors at the trail head, doing "bag counts", full or empty. Absent their assigned bags, have them run back up the trail to retrieve theirs...hmmm...probably won't work either.
Okay, I will back away from my "vacation backpackers" statement and say that the blame for the trashing of the backcountry can be shared across the spectrum of hikers and packers, not just the occasional travellers.
Happy hiking, my friend.