I heard this again on the news the other day: The original Model T Ford, launched 100 years ago, got 25 mpg. Since then we've split the atom, put a man on the moon, and invented spray-on cheese. All these technological advances, and yet the average gas mileage of our car fleet today is barely 21 mpg. Clearly the auto industry is ripping us off, most likely in cahoots with Big Oil.

The whole 25-mpg Model T story started with an ad devised by the Sierra Club to embarrass Ford during its centennial celebrations in 2003, which unfavorably contrasted the 16-mpg Explorer with Henry's flivver. Never mind Ford's own Web site claims the Model T got 13-21 mpg (but of course, say the conspiracy theorists) the Sierra Club's 25-mpg number is now accepted as fact by credulous media outlets.

The Sierra Club didn't explain exactly how it arrived at 25 mpg for the Model T, but no matter. The comparison with modern cars is nonsensical anyway.

The 1908 Model T was powered by a 2.9-liter four-cylinder engine that developed 20 hp. It weighed about 1200 lb, and could probably hit 45 mph with a good following wind. Even if it did get 25 mpg, next to anything Ford sells today it was also crudely made, terrifyingly unsafe, and a gross polluter. It didn't even have air-conditioning, a CD player, or cupholders. But hey, let's not let the facts get in the way of a good ad.

So the 25-mpg Model T scenario is now regularly trotted out by unthinking media and eco-bloggers as evidence of the auto industry's shameful foot-dragging on gas mileage and global warming. Oh, really?

Almost 10 years ago, Volkswagen offered a high-efficiency version of its Lupo city car that made the Sierra Club's poster car, the Toyota Prius, look like a gas-guzzler. The Lupo 3L was powered by a 1.2-liter three-cylinder turbocharged, direct-injection diesel engine that developed 61 hp. Extensive use of lightweight metals such as aluminum and magnesium for the doors, hood, rear hatch, seat frames, suspension, etc., kept weight to just 1830 lb, about 1000 lb less than a Golf.

The Lupo 3L had a five-speed DSG transmission, an automatic stop/start function that meant the engine did not idle uselessly at traffic lights, and low rolling resistance tires to reduce friction. It had airbags, anti-lock brakes and stability control. It could reach 102 mph. This was state of the automotive engineering art, a real-world car that met real-world safety and reliability standards, and delivered a real-world 78 mpg. And it tanked. Only 28,000 were sold in six years.

Why? Good question. Perhaps it was because the Lupo 3L was slow in traffic, its economy-optimized transmission was clunky, the seats hard, and the low rolling resistance tires noisy. It had no air-conditioning and no power steering (they were optional, but if you ordered them, your 78-mpg went south). Oh, and it cost about 30 percent more than a regular Lupo.

VW's ultra-efficiency car proved winning the fuel-efficiency game is all about compromises and trade-offs and expensive technologies, a point far too many commentators fail to understand. I'm astounded at the folks who recoiled in shock when Bob Lutz said the Chevy Volt would likely cost $48,000 (I think GM will actually sell it for less). GM is developing a whole new powertrain architecture, and the cost is being loaded onto one vehicle. That's why it's expensive. Toyota lost money on the first-generation Prius for exactly the same reason.

So maybe we ought to forget the spurious comparisons with the Model T and the simplistic finger pointing. Maybe the real question to be asked here is not why the auto industry won't build ultra-efficient vehicles, but why -- so far -- consumers don't seem interested in buying them.