BD,
For one thing, it's that same ostentatious consumerism you mention that fuels (no pun intended) our economy. Smaller, more conservative lifestyles means less buying and spending, which means less demand for consumer goods, which means...well, I imagine you do understand at this point where I'm going. Much of our commerce today involves goods and services that people buy simply because they CAN afford them. Decrease demand for these products in order to afford gas, and you decrease the need for jobs to produce them, revenue and taxes from selling them, etc. I'm not saying we couldn't get by without these things like the Europeans do; I'm saying the way we're currently structured, we've grown socially and economically dependent on them.
We've also become dependent on transportation to balance (1) the ideal location of our homes and (2) having the ideal job. Seldom do the two occur within a mile of each other in sprawling America. We're a nation of suburbs where it's not uncommon for people to drive 20-40 miles round trip per day to work, part of the way through gas-guzzling traffic. I personally have a 35-mile round trip commute, and I know many at my school who travel considerably farther. Outside of major cities, we don't have the kind of public transportation system to handle these commutes. Therefore, rising gas prices have a higher effect on the commuter in suburban America than on Europeans who either live in the cities with public transportation, or who live in small towns and villages that are more or less self-contained and who seldom go to the neighboring towns or cities except on special occasions.
Free-spirited tourism is also a part of our culture, and much of that is dependent on the ability of the family to jump in the station wagon (ok, updated since National Lampoon's Vacation to the SUV) and drive the kids to Wally World, or the adults to the resort, or the Grand Canyon, or whatever. The bulk of American tourism is based on automobile traffic, not mass transit such as airlines or trains. Therefore, the individual consumer in America is hit harder by travel expenses and is less likely to vacation than the European who has been used to jumping on a bus or a train and sharing the expense with dozens of others, and therefore our tourism industry takes a bigger hit when fuel prices rise.
As for trade, we are also in the habit of shipping more common goods over greater overland distances; European production tends to be somewhat more localized. You can find oranges from California in your South Carolina grocery store anytime you want; hammocks made on Pawley's Island are shipped to Colorado, huge farms and dairies ship meat, veggies, and milk in all directions...local mom'n'pop businesses have been all but eliminated in favor of production giants that are dependent on...you guessed it...shipping. Europeans are very trade-oriented, yes, but check the European road systems and compare their average overland shipments to the vast fleets of 18-wheelers pounding our highways in this country who are now looking at double the fuel expenses of just a couple of years ago. Since very few things are locally made or grown, when fuel and shipping go up, prices of almost everything go up.
Perhaps if not apples to oranges, at least a Macintosh to Granny Smith comparison...you mention most of the Europeans YOU know being far more traveled than the AVERAGE American. This is not necessarily evidence that the AVERAGE European is FAR more traveled than the AVERAGE American...just the ones who are worldly enough to have come in contact with you. Besides, we don't consider Americans "well-traveled" because they've been to the neighboring state--even though in some cases that trip may match or exceed the mileage required to see three or four European countries.
I agree in some cases about the stereotypical "club soccer family" with the big suburban home with the big Suburban gas-guzzler, but as soccer expands and gains popularity as a sport, more and more "average" athletes and families are becoming involved--some of whom have to take the difference in gas prices into account when deciding if they can travel to practices several times a week and games halfway across the state, no matter what they drive. It would be a shame to see soccer get even more of a reputation as an "exclusive" sport because only the elite can afford the transportation required to participate in club.
I was very brief before because I was pressed for time...I apologize if my previous lack of detail hindered your understanding of my point.