It never ceases to amaze me how people scramble to defend the EU's failed policies over the last three decades. The EU managed to regulate itself out of all relevant markets and it only has itself to blame.
The ‘American dream’ attracted a lot of talent (look at how many tech leaders were immigrants), and once the network effects (both IT and social) kicked in it was hard to stop. This is a story that has unfolded many times throughout history. Talent moves to where talent is. And it will move if conditions change.