How come so many engines and tranny's?

I've got 241000 kms on the V6-MTX and it doesn't even use more than 250-300 mls. between oil changes ( every 5000 kms).

Just changed the serpentine belt cause it failed. Should have done it at the 160,000 kms mark for safety.

Will need to do the rear ebrake cables and rear disks and another left front wheel bearing.

Does anyone else have this recurring problem?