The Chevy ads were a worst case example, but were mainly there to illustrate the point that there seems to be this rampant culture of competition prevalent in North American culture. For instance, every car ad says their car won such and such an award, and was voted consumer choice of 20xx, and it's just plain ol' better than brand y. There are pharmaceutical ads that run for 2 minutes just so they can list all of the adverse side effects the medicine will cause (yet you should still ask your doctor if obesotol is for you), and never ending lawfirm informercials that encourage you to sue the shit out of everyone and everything because hey, you're entitled to your compensation. Then you step into walmart and you can buy giant cases of anything for a fiver sometimes less, and outside there are blokes complaining about the cost of fuel leaning fully upright on their latest 4 wheeled monstrosity. It truly is a culture of excess and frankly the cost to other people in order to sustain it makes it undeserved.
Please understand that while what you mentioned is very true (especially the law / drug ads if you watch CNN news during lunch hour) not every American should be lumped into the same greedy/wasteful category. I abhor TV and personally believe it dumbs down the masses and promotes a culture of laziness and complacency. My vehicle is almost 10yrs old and has been paid for long time ago. My wife and I are professionals (accounting and engineering), yet we live in a small home that we can easily afford. Yes, even though our friends with barely a high school diploma have much bigger houses, new cars (which most of them lease by the way). Many are already on their 2nd (!!!) house despite not having any equity in their first ones (thanks to interest only loans). I do all my own home improvements/repairs/yardwork and we eat breakfast and dinner at home, leftovers for lunch. 3-4 times per month we go out for coffee on Saturday morning as our only "luxury" that we allow ourselves as a family. Hey it's boring to eat in every day! My wife saves coupons and sews buttons back on clothing. We don't have a nanny. We don't have a housecleaner. We recycle. We only buy healthy fresh fruits/veggies/meats, nothing preprocessed. We don't have ipad this, ipod that. My PC at home is a 8yr old machine I built from newegg parts. We put as much as we can away into our retirement funds, and have already been contributing to our child's educational fund. We have not been on vacation in over 3 years. My vacation time has been spent painting or drywalling my basement. As for purchases, my general motto is "I'd rather go without than spend money on something of low quality." So over the years I've collected a variety of, say, nice tools which will last me a lifetime instead of heading to Walmart and buying up their disposable "tools" made of mystery pot metal. My point is this: even though we have the income to live more lavishly / wasteful, we make a conscious effort *not* to. This makes my wife and I statistical anomalies in our age group (25-34yrs). Don't paint all americans with the same brush.
"I'm a mean green mother from outer space" -- Audrey II, The Little Shop of Horrors