Depends. More coastal areas could raid India which is usually significantly less defended than the massive empires of the levant. The Jewish kingdoms of the Himyars could unify a lot of the surrounding tribes, or the Himyars could move into Ethiopia and become basically Jewish Swahili. However, the Byzantines and Sassanids both have a vested interest in maintaining influence as far as they can, and if one or the other cracks Arabia will fall not long after.