The miles before the pump fails is irrelevant, it fails after hours of operation not miles.


1 car could have 150k miles and driven X hours (lets say lots of freeway driving)

2 car could have 75k miles and driven X hours (lots of city traffic stuck at lights)

They could both have the same amount of operating hours and the pump fails around the same time.

Of course when people say the pump failed at 30k or whatever thats just a defective pump.