Besides the oil barons in the Middle East, there is a great lack of education and dependable jobs in numerous Middle Eastern countries. One might want to consider what kind of sociological and psycological impact this has on young males in the Middle East. Perhaps this frustrates them and leads them to all sorts of the worst kinds of religious and political extremism.
I do not say this as a point to exuse their ultimately unexusable actions, but perhaps as a prospect for future solutions to many of the social problems in the Middle East.
Besides BinLaden was a billionaire and the Al Queda guys in the states were not poor....far from it.
Sure if their economies were growing they might not be so bitter but Islamic law forbids the charging of interest among other things. It is no coincidence that Turkey is so much better of than the other Muslim countries, they have a secular government.