I don’t know that they could be driven out of Syria. Currently, the only people who fight them on the ground are Iraqi Security Forces (i.e., the Iraqi army), Shi’ite militias which are trained and often lead in combat by Iranian “volunteers” and Iraqi Kurds. Although they have gone into Syria after them on occasion, there has been no large scale efforts to destroy or force the withdrawal of ISIS anywhere other than in Iraq. This is a problem which is not going to go away on its own, and which would require major ground forces if one intended to actually destroy them.