I think at least part of the reason is, that efficiency can more easily be sold as convenient. The message is, you can save the environment by purely technical solutions without any personal commitment.

And I think in Europe it is mostly not that way at all. Gas taxes are gas taxes, independent which way you are going to buy less gas.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers

To be fair, anyone buying a car has the immediate option to use less gas.

Whereas going from a big sprawl to a low footprint city is not under the immediate control of the person making the decision...

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi