LOL.
Have you taken the USMLEs? Having taken training, licensing and certification exams in two countries, I can tell you that the USMLE and ABS exams were much easier than the Royal College exam which has a 30% pass rate.
The reason the Caribbean schools target Americans is because we are closer, have more money, more interest in medicine and are willing to pay for it. I suspect the reason Saudi pays for positions here is 1) the US welcomes money from Saudi and 2) the NHS likely prohibits people paying for training or its too hard to figure out.
There's no doubt that the US has great training and certainly better than many countries, but is it the best in the world? There are certainly great places outside of the US and on par with our education here.