There is an interesting site, that lists the originals and the "rip-offs" of Bob Dylan ORIGINAL?
The page also has a few quotes appropriate to this discussion.
If There's An Original Thought Out There, I Could Use It Right Now: The Folk Roots of Bob Dylan Matthew Zuckerman
"The world don't need any more songs. They've got enough. They've got way too many. As a matter of fact, if nobody wrote any songs from this day on, the world ain't gonna suffer for it." Bob Dylan, 1991