“The Saudis would have to hire mercenaries to fight for them”
The only ones they could hire fast enough with any sort of skill would be the Israelis. Perhaps the Saudis could hire recently-retired US Air Force pilots. Just guessing, really. A pilot can be a pretty good pilot, but plop them into an unfamiliar airplane and they would probably suck. Perhaps I am misreading the situation, but assuming the premise, eg; that a war is imminent, I see little possibility of a ground war. It would be all missile, all air. Very fast. I cannot see the Saudis, unless they are very stupidly arrogant, thinking anything but that they would be wide, wide open once the 1st, 2nd, and third round of missiles were expended. I am kind of doubtful about the whole story but far stranger things have happened in that corner of the world.
“I see little possibility of a ground war. It would be all missile, all air.”
They both have significant Naval forces, and huge naval interests - both of them ship the bulk of their oil out by Sea, through the Arabian/Persian Gulf and Straits of Hormuz.
Iran has it’s biggest Naval Base at Bandar Abbas, right in the Straits of Hormuz. It could well be the main focus of a direct war between the Saudis and Iranians.
“The only ones they could hire fast enough with any sort of skill would be the Israelis. “
There’s also “Little Sparta”, the UAE:
Those weapon makers such as Lockheed Martin have been racking in the Giga Bucks for a long time now even without the middle east sales. Now with the increased tempo of the war drums between these 2 sponsors of Islamic terror I'd say let loose the dogs of war. However my SOLE concerns is the inevitable increase in the price of oil.