i definately agree that there is a cycle. My uncle got in in the 80's and he is shocked at how competitve it is. He was recruited by schools, and he had a lower GPA than me...and i'm struggling. I see apps starting to decline when 1) people that are getting in now realize they hate it, and don't encourage others to do it, and 2)when the economy changes.
Also, i'm sure there will be aspects of dentistry that become unappealing to people.