"Let's say you've got a 10-year old Camry.
Motor is shot, you go to the dealer for a new one.
I guarantee you that the parts and labor will cost more than the car is worth.
Not too unlike replacing a battery pack at high miles on a hybrid"
The thing is that with any morden engine is almost garrateed to last far more then 10yrs without a costly replacement to keep them on road. On ther other hand, after 8 year of so you are pretty much on your own, and IT WILL fail, just a metter of time.