Sorry, but I always find these "I write so much, I'm bound to repeat myself" arguments rather weak. Not that I have written all that much music myself, but when I have done so, I am keenly aware what my previous stuff has been and try to avoid it. And I would say most artists have this aversion to repeating themselves, including artists who have had a career for 50 years.
Reality is, like it or not, but Neal has somewhat of a Lego approach to his music. He has fixed elements he plugs into his songs, and that regularly causes repetition in his songs. He essentially "parked" the Wind At My Back chord progression for a while, and the same for the Devil At My Throat thing. Whether him pulling them out of park position was intentional (in the sense of enough time has passed, let's reuse this) or unintentional, who knows. But fact is, Neal has a problem with self-plagiarization.