Two reasons that Switzerland appears to be so prosperous. One is the banking laws that draw depositors worldwide from the richest of people. Even other countries keep their money there. Switzerland has been a repository for the wealth of the world for a long time. That is one of the reasons they were allowed to remain neutral during WW2. The second is the pharmaceutical industry is largely located in Switzerland. The near impossibility of immigration is due to the laws requiring people to show they have employment or substantial wealth on their own not to be a drain on the government. This combined with the extremely high cost of living keep immigration low and the population homogenous.