I know that there are aspects of these societies that are socialistic, but that is true of every economy that I know of. There are also sectors that are preindustrial nomadic. However, Americans can collaborate with those who want to be capitalists and build a modern society and we have in Saudi Arabia. They have money and we show how to turn that into profitable business. That is what capitalism is.
If you take oil out of the equation there would basically be no capitalism there at all, nor would there be "the highest income per person in the world" in the world. Look at Muslim countries that don't have oil, in contrast the US was a wealthy capitalistic country before oil.
In short, "the highest income per person in the world" is not because of their society, it is because of oil money. They didn't look for oil, they didn't drill the first wells, they didn't pump the first oil, it was someone else, and now because of capitalism from the outside, not inside, they can afford the wealthy welfare state they have.