Urban sprawl and the need for individual transport and decreased focus on mass transport all contribute to our (USA) problem or rather why we seem so far behind than other nations who have had to contend with inflated prices for so long.
But if Europe adopted stringent environmental regulations as those in CARB, I doubt many of their vehicles would be up to snuff.
As to the skirt issue, I bet it's down to cost vs gains. Is it worth the money and time to design and create a removable panel for the minute gains that could be made up with smarter driving? I recently had an argument with my parents over this (I had attached rear wheel skirts) and they kept saying "well nobody else has them so they must not work!!!" line of reasoning. I start countering with aerodynamic drag and it flies over their heads faster than any deflector.
