Chinese Workers Abandon Silicon Valley for Riches Back Home

I am a Norwegian in Silicon Valley that have spent most of my career with Chinese colleagues, both in academia and industry, and my anecdata seem to indicate that my highly talented China-born colleagues are sadly leaving because;

- China has great opportunities for riches

- Getting a US VISA is hard and painful when you come from a populous country like China or India

- My China-born colleagues seem to in general be more conservative, and Silicon Valley has become violently intolerant of anyone that holds an opinion different than the predominant view

Only the first reason is somewhat objective, while the two others cause stress in their daily life as their ability to provide can at any time be removed due to what is perceived as arbitrary reasons. Everything being equal, many of them have told me they would prefer the less crowded Silicon Valley.