I think that this is one of those things that pose a simple question to which there isn't any simple answer (like the "Why do we die?" thread).

Living where I do, it appears that every other vehicle on the road is either an SUV or a BHP (Big Honkin' Pickup). Some of these are necessary; this is, after all, ranching and farming country. But I have a hard time convincing myself that the city councilman who lives up the street really needs a Ford Expedition to drive to and from his office everyday. Or that a local radio station needs a Hummer from which to do remote broadcasts from stores and car lots. Or that anybody living in town needs a Ford F-350 pickup truck to drive to the grocery store and the mall. (And I admit that sometimes these ARE needed, but not by Mr. and Mrs. Average Householder.)

There IS an area of greed. And production costs. And transportation costs (I can't think of many other products where you have to use the product to move it, which costs are naturally included in the consumer's price). And research. And lots of other things, including the fact that the US has made little progress in alternative auto fuels since the 1970s (lack of leadership and motivation).

Most things, I've found, are like this: no simple answers.

Petrol has topped USD 2.00 per US gallon here, for premium. I'm glad I drive a Honda Civic and get about 28 mph for city driving!