Let them throw their tantrum. The goal here is the world vs. KSA
They will find that their citizens cannot eat and drink oil.
If anything, if the Saudis make oil more expensive, they'll do quite alright. Granted, the Saudis can't keep the price high forever, but the Saudis still have a large enuf share of world oil production to be able to impact the price. That said, I wouldn't expect them to pull that particular trigger, if only because I don't expect the US or the EU to do anything beyond words right now. However, some other countries could see a sudden loss of economic support. Basically, this is their way of telling other Arab countries to keep quiet or suffer the fate of Qatar.