That "something" is the huge, relatively homogeneous, english-speaking and thus very "international-by-default" single market. It's the one and only actual moa

That "something" is the huge, relatively homogeneous, english-speaking and thus very "international-by-default" single market. It's the one and only actual moat that the US has over Europe when it comes to developing huge corporations in the winner-takes-all online markets. Everything else (like better VC situation, more attractive environment for international talent) is just a result of this original moat and would have just as well developed the other way round if this one advantage had been on the other side of the Atlantic.