I'd shorten the list to one significant difference that's somehow avoided - Europe consists of different countries, with different cultures, interests and languages. That's one of the beautiful things in Europe, but let's not pretend it doesn't exist. Forget laws, they can be written, changing culture, interests and financial situations is huge. There is no country called "Europe".

But to do business through all European union, there's way more added issues at the beginning then compared to Silicon Valley vs. US (similar culture, values, interests, language) or eastern countries (China, Korea, Russia and their markets).