If nobody is playing NA fpl where's the motivation to even get better or to practice for other NA players? Think of the mentality of these guys, people in EU look up to players like s1mple for his hard work and dedication and it shows in FPL, that's why they get somewhere in cs.
Many top EU fraggers came from FPL because they had a lot of motivation to get in and be able to play with the top players in the game - they had the chance. NA doesn't have that. The top "idols" that an NA player can look forward with playing with people like tarik and stewie, neither of whom play much or somewhat seriously, only going for knife clips etc.. so that scene is dying, if not dead already.
tl;dr mentality of NA -> content creation, mentality of EU -> become the best. kinda obv when you think about it.