It's bigger and wider than that. Throughout the 1990s people didn't care what anything cost on the web because they figured the money would work out someday. There was the 2000s crash but the success of Amazon, Google and such proved that the web was a great idea.

The story of social media was that there was a narrow time window and a single place (other than, recently, China) where investors were willing to take a chance that the likes of Facebook and Twitter would find a funding model. By the time that model was proven, it was too late for new entrants. Thus Europe was left high and dry.