I like 'em too, especially for the torque! But the diesel reputation goes back to the old days when they were indestructible and ran for a million miles without much needing to be done to them. Modern diesel engines have turbochargers, direct injection, urea or other emissions systems, and all the electronics we love in the cabin. I would guess those "enhancements" plus normal cost reduction efforts have brought diesel life down, or maintenance frequency and cost up, or both. That's a guess, you can probably verify with some research.