My guess is that older gas engines failed sooner because carburetors tended to run fuel-rich which washed oil off the cylinder walls, promoting wear, especially while cold. Diesels spray fuel on the walls too, but it is more like oil so lubricates well. I think that is the main reason the bottom end of diesels lasts so long. New gas engines seem to last much better w/ modern fuel controls. Our 3.8L Chrysler has 210K miles and still excellent compression and no blow-by. I re-ringed our 2.4L during a head gasket repair at 100K and found the ring gaps still in spec and the honing marks still on the cyl walls. I think Mitsubishis are more commonly bought by young erratic kids who more likely neglect basic maintenance like oil changes and careful warm-ups, so last as long as a Camaro. May not reflect on the engine design.