After WWII, Britain annexes Eastern Lybia into Egypt, including most of Lybia's yet undiscovered oil wells. When Egypt gets its independence, it has an energy bonanza waiting for it. Now just eliminate some corruption and internal dissent, have them do better against the Israelis, and you've got yourself a North African economic powerhouse.
Egypt really has the largest "real" economy among the Arabs (I mean, in terms of agriculture and manufacturing). The oil-boomers...that's somewhat artificial.