They're really building that? Does anyone outside their little royal bubble think this is a good or even feasible idea?
There is no end of stupid ideas you can generate while you are rich and unaccountable.
Besides they aren't targeting us, but similarly stupidly rich people. Although I heard no one trusts them after the whole bugging bezos phone incident.
And they could get some money, tell some guys in hard hats to drive some tractors around the desert, wait a few months, "Oh, we ran into some difficulties/new economic reality, project cancelled. Your money? Hiring men to drive those tractors weren't cheap you know!" (Read: "The men were South Asian slaves but the construction company boss is driving a new Mercedes now, and hey, he's actually my cousin and we're going golfing tomorrow!")