ISIS is simply a return to the original jihad and its continuation thru many centuries down to the Ottomans.
Their problem is not their intent. It’s that they are utterly incompetent at running a modern society. Even a militarily effective armed force.
Their only true military advantage is the unwillingness of Europe and America to stomp all over them. That is simply no way to win a war.
These guys can’t build a tank or an armored car, much less build and operate a jet fighter. They probably can’t even build small arms.
The funding from their captured oil fields and from their petroprince supporters is drying up.