There’s just not enough smoke around in Saudi Arabia to suggest the fire you’re talking about. The gulf states are just too economically dynamic right now to be in any real trouble.
But if oil prices stay down for a couple years. Maybe things will change. But first the Saudis have to burn through about 800 billion dollars in reserves.
After that, anything can happen.
. . . and just where is that money invested - and what will happen if it is withdrawn???