Is Rev. Harold Camping just ripping off Terence Mckenna with his end of the world prediction?

End of the world predictions predate the birth of both (e.g. Millerites and the Great Disappointment--both years). Yes, there's good money in eschatology, so preempting each other is essential. As an ogy, Deep Impact and Armageddon were released at about the same time, and neither was original.