I'm one of those Americans who doesn't buy the cheapest ticket. I buy comfortable seats at convenient times with airlines I'm loyal to. Guess what I see none of? Any of those things! My bags are free, my drinks are free, I get to go to the front of the check-in line and, many times, security line. On occasions where I've been charged a change fee, a quick phone call gets it reversed. I board a 6:30AM flight tomorrow and am honestly looking forward to a few hours of cool views, relaxing reading and maybe a touch of alcohol.
Airlines tried competing on pitch and leg room. Their behinds got handed to them by travellers switching to budget airlines. If you want better service, there are business class tickets available at prices cheaper than pre-deregulation fares.
Note that this effect isn't constrained to Americans. European non-business passengers' demand for air travel is also extremely elastic with respect to price [1].
[1] http://dare.ubvu.vu.nl/bitstream/handle/1871/48303/140307.pd...
I'm sick to death of this meme that Americans are only interested in low prices. The fact is airlines were one of the first of many industries to use fees, line by line cost breakdown, obscure deals and a baffling purchase process to strand customers on an island of price comparison and nothing else. See also: cell phones plans.
If you knew what you were getting and could hold airlines accountable when they didn't deliver on what was purchased I promise you price would no longer be the only factor. This is not a truism about Americans you've found, it's a truism about distorted and manipulated markets lacking sufficient regulation.