1. You guy drive a lot less than us. I do trips three times as long as what would destroy me in Europe (twice a month I drive 500 km without stopping and back the next day)
2. Are you using the imperial gallon or the american gallon? Very common mistake (the mile used in the article looks like and probably is the 3.8l gal)
Edit, you're using the right gallon.
A larger car (more space, inertia and soundproofing) with a bigger engine (lower rpm therefore less noise) with more cylinders (less vibration) is more comfortable and wears you down less. And I loved my wife's no frills stick-shift Versa (4000 rpm at 80 mph really got annoying though)
As to American's driving large distances, based on my personal experience, there's no comparison. American cities are further apart, families are more scattered, families are larger. Don't forget that in many ways America is actually two societies in one. One America lives in places largely undistinguishable from Europe. The other has 90 mile one way commute (a colleague. Mine is only 17).
I can't think of any 500 km route in Europe that wouldn't destroy me. And a little engine screaming for dear life wouldn't help