tl:dr ISIS as a state is in on its way out. ISIS as a terrorist organization will be here to stay.
ISIS is squeezed on all sides now. Kurdish and Iraqi forces are advancing t words Mosul and Jerablus (northern Syria) all but taken. Turkey has finally sent tanks into Northern Syria. That's a big deal because Turkey has a relatively modern military and is in the top 10 world wide for size of active military. The US is still bombing ISIS targets as is Russia; add to that the small groups Syrian Rebel troops who are actively fighting ISIS. The Price of oil is low and that means ISIS makes less money from stolen oil and as there land holding shrink so do there potential for kidnapping and selling hostages. I think ISIS as a "state" has maybe 12 months . What emerges after ISIS as a so called state is finished I don't know...
Here is a tweet that Illistrates my point (at least in AlBab)
https://twitter.com/GeromanAT/status/766985180426833920
- GeromanAT
image Source: from above tweet