Oh, they could be anihilated relatively easily in very short time. There hasn't been interest in doing so by any country with the power to do it: china, russia usa or even possibly israel. In fact it was the US that created conditions for it to spring to life.
Hussein, kadaffi, Assad, they went and attacked/killed these and portrait them as incarnations of the devil. That is very stupid, those leaders were perfect for those countries. Look what hellholes they became after these leaders were removed from their chairs.
People critized sadam hussein and called him a murder, but what exactly is the right way to deal with the kind of people that makes up the ISIS as of today? Did he do so wrong? Would he get them under control with silly soft legislation like in western nations?

With less colateral damage than that already caused in iraq and afganistan in the last 15 years, it would be pretty straight forward to remove the isis of the map. But there is simply no country or political force with any motivation to do it.

That asside, I see a rather steady, and now rapid, exodus from the western delusional mindset of universal peace and silly assumptions that every third world person is a saint. Parties with more radical optinions both on the left and on the right will have their chance to try out different paradigms. EU might be dismantled because of this, many social assumptions such as tax paying, national defence, open borders, will be questioned and or eventually cease to exist. So I think the ISIS is having tremendous impact in the world, in the sense that they are opening people's eyes for the fact that assholes like them do exist and and more concentrated in some parts of the world and some specific ethnicities. This is a fact. Although I think that as soon as they try to set foot on any minimally functional country they will be stoped like a cockroach. The most direct candidates are of course turkey and iran, but even egypt could easily beat them