Mark's a very slow human being as he said himself multiple times. If there's nothing pushing him he'll take his time - and it will take too long as we can see.
He is just being modest. 9 records, 4 film scores, 8 large and 3 small tours and a state-the-art studio in the last 20 years (plus all the guest appearances), one can only hope to be as productive as this man.
I tend to agree with Mark. He doesn't mean he's lazy and stuff, he says it because just compared to other writers/musicians/composers he's on "average" at best in the terms of quantity. Van Morrison have 37 studio albums (THIRTY SEVEN
), Paul McCartney have 24 + The Beatles (and The Beatles alone had as much songs as had been written by Mark over his whole career). Bruce Springsteen have dozens of live and studio albums and so on.
Mark, on the other hand, have only 14 albums for both DS and solo career and roughly 218 songs released (leaving instrumentals).
It's really not the highest achievements in the quantity department, but you know it's all about the quality. That's why we all love Mark.