No, it is not the weather. I mentioned that because Costa Rica is utterly delightful EXCEPT when it is raining.
American surgeons would not make more money in Costa Rica. Those that had lots of money could simply invest it in the US and not work at all. Others would be far more likely to migrate to an English-speaking country, or just to move within the US.
A competent surgeon will always be able to make a better living in the US than in Costa Rica. After all, to live in Costa Rica, one would need to have a good working knowledge of Spanish. There are many more prosperous nations where English is all one would need.
Again, I simply do not see this happening, and expect that we will see that it does not happen in the future.