I am missing something here. If you drive the car for 10 years why would it matter when you paid it off. Wouldn’t the most astute way of looking at it be Investment gains minus – interest paid. If I paid an additional 10000 in interest but earned 12000 by banking it wouldn’t it have lowered my cost of the car by 2K.

I think I know what you are saying. Most people don’t approach it this way and are more rechless with the way they spend but to the savvy person they can make out fairly well.