Last but not least, the US has NEVER gone to war much less begun hostilities for 'gain'.
We invade culturally and economically, all over the globe. Now, that's a good thing IMO, but we do invade and stay, just not in the typical way. Ask the French, who get all bent out of shape because our movies, computer stuff, fast food joints, etc. are everywhere.
That's another thing, and probably what has the Muslims so wired up. Cultures have clashed before but not with the impact or to the complete extent that the computer age has permitted this time. Muslims stood it off before but cannot now. Technology and politics have always been married but the situation is much more life and death for them than for us.