"The Hummer, on the other hand, costs a more fiscal $1.95 per mile to put on the road over an expected lifetime of 300,000 miles. That means the Hummer will last three times longer than a Prius and use less combined energy doing it. "
Having driven a hummer i would say it will never last 300,000. Maybe 100,000 if you baby it. After that it will be in the shop too much to make it worth keeping on the road. On the other hand, I could see a Prius easily lasting 300,000.
toyota pickups of the 1980s made 300,000 miles.
i've never kept a new vehicle longer than 125,000, i think, at most.