Why EU looses its best brains to US

Today's WSJ reports that according to a European Commission survey, more than 70% of EU-born recipients of U.S.-doctorates between 1991 and 2000 planned to stay in the US. Alltogether some 100.000 European-born researchers currently work in the USA.
The EC fears that by the end of 2010, Europe's knowledge economy will have a shortage of 700.000 scientists and engineers.
Why do so many researchers prefere the US above Europe in seeking career opportunities? Among the reasons given why U.S. universities and company research labs are so attractive are the following:

1. High quality of teaching and research (due to big budgets)
2. Allow for more freedom, less bureaucracy
3. More succesful in turning scientific discoveries into economically viable projects
4. Americans are culturally more embracing towards new technologies
5. Higher Salaries
6. Lower Taxes

I'd think turning these things around should have top priority of European Governments.