But is it really about gas mileage? Or is gas mileage just the excuse for something else – something even more sinister than a handful of people (this is what "the government" is) contravening what buyers want, as expressed by their willingness to buy?

Let's consider a couple of things that could have easily and inexpensively increased fuel economy; or rather and perhaps better put, made it feasible to go much farther on a gallon of fuel without adding complexity and cost:

Gasoline, for instance.

Not ten percent gasoline  . . . and 10 percent ethanol. Which reduces miles-per-gallon because 90 percent gas and ten percent ethanol contains less energy per gallon. An easy way to increase gas mileage without changing anything about the car would be to put gas – not adulterated gas – in the tank. The increase would be on average about 2-3 MPG, which is a larger increase than is achieved by engineering artifices such as replacing relatively simple fuel delivery systems like port fuel injection with high-pressure direct injection, which also adds to the price of the car – negating the smaller mileage benefit achieved.