There’s a lot of stuff you stumble upon via Google Public Data Explorer which you kind of knew, but is made all the more stark through quantitative display. For example, consider Saudi Arabia and Yemen. In gross national income per capita the difference between these two nations is one order of magnitude (PPP and nominal). Depending on the measure you use (PPP or nominal) the difference between the USA and Mexico is in the range of a factor of 3.5 to 5. Until recently most Americans did not know much about Yemen. It was famous for being the homeland of Osama bin Laden’s father and the Queen of Sheba.
Let’s do some comparisons.
Good luck Saudi Arabia! 
Couldn’t happen to a nicer nation.