It's weird to quote the Islamic State, but honestly, this is a pretty effective sales pitch to Americans for a group that otherwise doesn't have a lot going for it anymore:
Don’t you see how you became the laughingstock of the nations, and an old and crazy man controls your fate, whose opinion changes between morning and evening?That works a lot better than: Join Daesh, after you're killed, your family will be left stateless diseased and half-starving in a third-world prison in the middle of a war zone!