Even longer term would be the question of family size. You hear people who have those big SUVs whine about how they need the thing to haul around their large families. One might argue that having a large family is perhaps a problem in itself, but once you have the kids there isn't really any going back. It won't be until the kids grow up and move out of the house that the parents would finally be in a position to do this.
you are the media you consume.
Not to mention there's no reason you have to get 12 MPG with the monster car. A friend has a Mercedes 8 passenger bus for his biz. Gets 22-23 MPG. (Diesel)