Perhaps because the US is the home of a number of prestigious colleges and to be with your peers you have to relocate there? You act like the broken healthcare system is the only possible explanation for cases where the US provides better care, but I'm yet to see that proven. Intuitively it doesn't track because many of the issues with the system don't pertain to things like intensive cancer care but to simple things that are of the exact same quality in countries with better systems, such as insulin where the only difference in the US is the price.

Not to mention, your comparison on cancer survival rates is flawed. The US system drives many people with cancer to be completely unable to afford treatment, which I doubt you've factored into your survival rate number.