If another war occurs after Syria is over with, then while i agree it's up to the locals own issues (Tribalism), but all these lines were drawn when Britain and France decided them in the first place. Then we were told to shut up, and the Americans took over, making Sunni Islam it's preferred market and directly pushing Wahhabi agendas. Emboldening one side was always going to cause friction.
You can't just blame it all on the locals.
It's no mistake that ISIS was Wahhabi extremism at it's worst, not that it was the desire of the west to create such an unfortunate group of people, but it indirectly did it nonetheless.
It is often overlooked that BSG style when it comes to the West and the ME "all this has happened before and will happen again" - we've been bombing the middle east with aircraft for over 100 years but that is glossing over some deep rifts within Islam itself and the tribal nature of the area - there is not a chance that the area could see real peace any time soon even if the West had never got itself involved.