Don't want to stray off topic too much, so last post i will make about this. But I understand why there is an impression that gulf state countries are somehow richer than developed economies such as Germany or the Netherlands. Its not true. I've worked in both regions, and financially i was better off in the Gulf. But that applies to middle class and above, and the main reason is distribution of wealth/income and the fact there is no income tax.
More than half the workforce is blue collar. There is no welfare state or social benefits for these people. There are no minimum wage laws, labor unions/collective bargaining is prohibited. What that means, it costs companies less to pay the other 50% of workers high salaries, and they can shift a bigger share of the pie to them too. The state does not have any obligation towards the former either. A bigger concentration of a smaller economy goes to those at the very top.
The Netherlands has half the population of Saudi Arabia, and is a much smaller country. Yet it has a bigger economy. The Netherlands also has a higher GDP per Capita than every single Middle Eastern country. It is by every measure richer than every Middle Eastern country. Yet of course, you don't hear of rich Dutch princes buying up European football clubs