@Fido,
I am not so sure you are right because we might well have worn out welcome, but it seems to me, that Al Qaeda has too.
If we look at the so called Arab Spring (Not sure that means which is why I called it "so called") it seems that young people are turning to other ways to raise themselves up rather than turning to extremist groups. I am hopeful at least that eventually, the people in these countries will solve their problems in their own way in their own time and will have no need to worry about the US, especially if we are not there imposing ourselves on them.