like it's big, elaborate build outs, nothing delivered, and some sort of under the table deal nuclear with Trump's brother in law that got him a Billion. the Iranians have, or can rapidly enrich, and Israel is popping off again (and may have ~100 nukes), so Saudi has means, motive, opportunity.
infrastructure required to build silos, and infrastructure required to build the City Of The Future are going to look more or less the same for 3-4 years -- lots of big holes, running trenches, piping and power, etc. -- and after a few years they can call it a failure and quietly sweep it under the rug with the rationalization that it's been a failure and they're ashamed of it.
