[adventured]

To build a Google or Facebook, you of course also have to get the US market.

So you have to accelerate to massive scale across Europe, and then conquer the US market before a US company conquers the US and spreads across Europe. It's clearly a far more difficult proposition for the European company. The only alternative I can think of that might work, is for European companies to start with targeting the US market first (a challenging concept in its own right - to target a foreign market first).