Anonymous coward( 'Bull Fucking Shit', below) is far too strident; but it is the case that there's a curious sort of 'bifurcation' in the 'terrorist' labor market(a confusion we probably contribute to by conflating the various local tribal militias, warlords, strongmen, etc. who cause us trouble during our ground campaigns with the 'terrorists' who are much more international in scope).
On the one hand, as you say, the terrorist grunt supply is heavily drawn from frustrated young men(inconveniently, lots of prime recruiting grounds have demographics that skew fairly young, so there are lots of them), with limited economic prospects, often compounded by a culture where you probably aren't getting laid unless you've achieved enough economic stability to get married. The miscellaneous 'insurgents' who raise hell when you attempt to occupy their home sand trap; but lack international ambitions and/or capabilities are mostly these guys. Some of the lower-skill terrorists proper are as well(particularly for the Israelis, since Gaza's festering-prison-slum atmosphere provides an endless supply of the angry and hopeless; and you don't even need to buy them plane tickets to have them go do a 'martyrdom operation'.
On the other hand, a lot of terrorist leadership, and high-skill recruits(if you want to blow stuff up, it sure helps to have some real engineers and chemists around), are not driven by economic desperation. Bin Laden himself was basically a trust-fund fundamentalist, and a lot of the more influential and logistically important figures are people with decent university degrees, often in marketable subjects, who are financially stable; but alienated by some aspect of the injustice of the world, or disaffected by secularism or the wrong sort of religious practice, exactly which one varying by person.
They come in both flavors.
