Ha - and they don't even take into consideration the most common scenario, which is far worse - for the car manufacturers, anyhow.
My wife drives a '96 Ford Explorer with every possible option from the dealer. Believe it or not, the damn thing actually gets worse gas mileage than my Supra - it costs more to run, even considering that she buys econo fuel and I buy 94 octane.
She wanted to trade in her Explorer for something more fuel efficient. So, I set her down and explained the facts.
Probable trade in value on her Explorer - which we own outright: $6000.
Cost to purchase the Prius: $24000 (After taxes, etc, etc)
Difference: $18000.00
How much money in gasoline will she be saving - about $20 / week, or $1040 per year. So, straight up, it's going to take about 18 years to pay off the Prius with gasoline savings.
Now, consider the fact that I can take that $18k and put it into an investment fund that will make me at least 7% - that's $1260 per year. Hmm... if I take the dividend from the investment and put it towards gasoline for the Explorer, I still come out another $220 ahead every year. And consider that I now own $18k in investments, which will grow in value over time, as opposed to a new car, which will drop in value dramatically over time.
Wonder what those SmartCar drivers think of that?