Always wondered about this. The US market seems to be more front loaded in game sales while in Europe they show more legs.

Any logical explanation?

More casual gamers? I don't know...

Games are more expensive in Europe, and people are(overall) poorer than in the US. That's just a guess, but maybe this is the reason why games sell less in EU during the first weeks, and have better legs later (cause of price drops that often occur).

Europeans are poorer than Americans so they are more likely to buy games on sales later.

In some countries, sure. Europe have several of the riches countries in the world though.

American culture obsesses over new shiny things so everyone has got to get the game right when it comes out. Europeans probably care about this a bit less.

The Op didn't specify so I just looked up the average salary in Europe and the United States. 

Pre order+ Price drop culture of USA vs Europe. Games are cheaper in the US, so $60 at launch isn't that much for a lot of people to impulse buy or Preorder a shiny new game. Price drops happen quick too for games that can't hold value for very long, while everything else that has value ends up getting a holiday deal. Leads to no legs or only legs during the holidays. Europe holidays are less substantial, but price cuts feel much better over the course of a year thus better legs.

In fact yes, if we talk about median wages, western Europeans are poorer (except for some smaller countries, like in Scandinavia, the Benelux, Ireland, Switzerland or Austria). It's just that our living conditions are overall better (less inequalities, free education and health, social programs, etc...), but the wages are not that high, and Europe is not as much a consumerist society as the US... But to go back to the topic, game prices are also higher here, which probably plays a big part of why first weeks for a game are overall weaker than in the US

because the US is full of people who stick to trends like herpes on a whore :v
old music games movies get the short end of the stick in the eyes of my generation