Most of those 113 million passports are recent I suspect and only because of rule changes on traveling to Canada, Mexico and the Carribean ... Where in many case people could do that with just a drivers license.
I agree that the reason we aren't using big planes like the A380 and the 747-8 are due to the frequency of flights that the US consumer wants from point A to point B and the cost effectiveness of the smaller planes.
What I would find interesting to learn though is a comparison of the major US carrriers vs BA, KLM, AF, LH in terms of compensation costs ... As these are all airlines thAt have some history to them and have had to overcome similar issues I suspect as far as aging fleets, contracts with employees, etc. Comparing to Airlines grime,raging markets in the Middle East and Asia isn't fair probably for a couple reasons as many of them are newer airlines or don't have the same long term employee labor contracts, have gov't support or funding ... Etc.