It was made a mess before and after WW2 and it never was allowed to self correct. If anything the powers that be kept trying to keep it bottled up until a few set pieces fell and the house came tumbling down. This isn't to say that going into Iraq didn't cause part of the problem, that simply revealed just how force the Saddam regime was applying to keep it all together.
Letting Libya fall like everyone did was likely the real issue. That whole country went without anyone trying to step in and allowed groups to assemble. Then the misguided interference with Syria by the US just sent the whole region to hell. You would have thought Libya would have given the administration a hint what would go wrong, let alone an Administration so hell bent on reminding people of Iraq repeated that mess twice if not worse.
The region has to reshape itself. What the West must do is try to minimize the civilian cost. This does not mean going in a setting new borders, but mostly protecting those who get out and making sure they have safe exit points.