There are many factors. Culture, Market, Tax system etc. One of the major factors is the environment and building the culture. Many of US tech success companie

There are many factors. Culture, Market, Tax system etc. One of the major factors is the environment and building the culture. Many of US tech success companies are founded or driven by European(and Asian) expats. So there is nothing wrong about Europeans themselves. It is rather the environment. That is why Berlin is doing a better job because they could make a better environment comparing to most of the European cities. Europe is not paying enough attention to how they are lacking there, considering how tech is going to play a crucial role in industries and the future economy. Europeans are also really busy with the political mess that US is building around them (ex. Middle East, Russia, Immigrants coming from conflict zones) and for a society that is just recovered after WW, that means not being prepared to accept expats as it used to be in last few decades for Silicon Valley. Therefore they don't have diversity factor which is one of the biggest advantages for Silicon Valley.