I have read Jared Diamond's book about the collapse of civilizations. He made a big case for the conservation and responsible husbanding of resources. I'm not sure how relevant it is to compare to the WT situation.
I think the WT is more headed on the trajectory of being a smaller religion with greatly reduced scope rather than disappearing entirely. Similar religions like the Mormons, SDA, and the Worldwide Church of God have gone through major changes and still survived, with varying success. The Worldwide Church of God nearly collapsed, but it is still around.