The Saudis have just lost their war against Yemeni rebels. They might as well come to terms right now, because the other 50% of their oil capacity is dependent on whether the Houtis decide to hit that as well. The thing is that this was not a massive strike by aircraft costing millions of dollars. This was an attack by aircraft that cost hundreds of dollars. Aricraft like these:
What should be noted is that everything in these things, with the exception of the boom, is readily available from online sellers and used for other legitimate purposes. Need a guidance system? Raspberry Pi, a GPS expansion card and a motor and servo controller card. You are good to go. Motors? The only question is electric or gas. They come in all sorts of sizes and they are delivered to you. A little work and some testing and you have a weapons system that can really hurt the world’s largest oil producer. Welcome to the 21st Century.