Because most are difficult to get to. Most of the time you need to remove/drop the fuel tank to get to the access to replace it. Not all fuel pumps are that expensive though. Dealership parts do generally have a bit more markup than 'normal' though a LOT of that depends on the dealership. -- Brian
"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain