Few reasons:
Best selling cars in europe are all small cars:
List of best-selling automobiles in Europe - Wikipedia, the free encyclopedia
VS US best selling cars/ trucks There arent any small hatcbacks on that list which are more fuel efficient in most cases:
Top-selling cars and trucks in the US in 2012
Also as mentioned above most people are afraid to drive with small cars because most cars are those trucks like F150 which drive like lunatics there because fuel is cheap.
Worst selling cars in the US:
http://www.goodcarbadcar.net/2012/08...ling-cars.html
Car manugfacturer needs to sell about 100000+ cars per year to be profitable. So around 30-50 thousand per year wont make any profit. There are many eco models in that worst selling list...
In Finland gallon of diesel is 7,54 $/gal and petrol costs 8,16 $/gal
There are also those big F150 and bigger in Finland but the drivers don`t have the money to drive even according to speed limits in their pockets
. They usually drive 80 or some 100 km/h.
I will propably make a sticker to my car this summer that Can`t you afford to drive faster with your truck. I am usually on the left lane on motorway speeding way over the limits and burn under 4 L/100km fuel consumption or 59 MPG us.
By the way best selling car in 2012 Finland was Nissan Qashqai in front wheel. Biggest reason for that is that its pretty cheap and big car so you feel also safer because you sit higher than smaller cars out there. Also many people buy the 4 WD version, because they think they need it drive on icy roads or they summer cottage road.
I have driven to many places with my lupo that has 80mm ground clearance than some SUV drivers with their 4 WD trucks that are marketed as off road capable. If driver does not know how to drive that 4 WD will not help much, specially those cheap market trick 4WD which are only 2WD drive cars in bad situations.