(Sorry I'm late coming to this thread - thanks Richard for starting it. I still haven't had time to read it all yet)

In the most unlikely event that "Mr. Tambourine Man" is still remembered by anyone a hundred years from now

Leaving aside the issue of whether the world itself will survive another 100 years, why do you say it's unlikely, Don? It's already been around for over 40 years and still well remembered.