Germany: Foreigners setup a third of all businesses

Here is an interesting article about foreigners that start businesses in germany. Since I'm an immigrant to the USA myself I have some personal idea's why so many foreigners in germany start their own businesses.

1. Immigrants want to show that they can do it abroad to themselves, their families and they want to be as independent as possible. After all what's the point of leaving your home country if you don't do better abroad? It can be a significant confidence booster when it works out.
2. The lack of a reliable support system. You move but your family (e.g. brother, sister, uncle, aunts) doesn't and therefore many things can become more challenging. You also need to earn more money to go back and visit them on a regular basis. In addition to that there can be other reasons like for example the US health care system or social security system who are not nearly as good as Germany's therefore you're forced to be more successful in order to have the same social safety.
3. You want to achieve more career wise and personally. For most people that's the main reason to move to another country. It might be a career opportunity you couldn't get at home or you have a chance to live in your "dream place". When you start in that new country you usually have no or not many connections and so you can throw yourself head over into work and build something.

There are obviously many more reasons why people migrate to other countries and build their own companies, but for me these were the main ones. What do you think why do people setup companies in their adopted homeland?