Anyway, I do agree in theory that the constantly lowering fare model cannot survive in the face of increasing wages and fuel costs, however I do not believe that the US is the only place that demands (and receives) low cost flights, as you seem to state.
I can only speak to Portugal because I've spent time there (dh's family is from Lisbon).
This drive for rock bottom prices regardless of consequences is very much an American mindset. (yes, I'm a born and bred NY'er so I'm guilty of the same thing).
As Bicker stated, we import junk from China and then we get all surpised and shocked when we find out that what we actually purchased is junk and lately hazadous to our health. the new Parents I know never ask about the safety of a toy, they ask about the price. If it's cheap enough it wins. It's not until all the recalls start rolling in that we become concerned.
I know in Lisbon and in Paris, you don't see the weekly "sales" and "giant" markdown mentality we have here. This is from a womens shopping perspective. You also don't see the "must have some thing new" every week that is very persuasive here. While my nieces love Ipods and cell phones like an American teenager, they wouldn't think of buying a closet full of new clothes simply because a new school year starts.
Food is another interesting area. I live in NJ and I always laugh when people complain about the price of strawberries in the middle of January. We seem to believe that we should be able to get a fruit that has to be shipped in from oversees all year long for $0.99 a pound.

uhm, hello how much chemicals do you think is pump into those strawberries and grapes to keep them fresh from Chile? and no one here in the states is going to pay 4.99/lb to have them brought in fresh, preservative free. In Lisbon the emphasis is shopping fresh and what's in season.
I'll give you my personal example. When my SIL & family decide on a trip to WDW, they plan the air around convienence and ease of travel first, price is usually the 3rd consideration.