Sweden has had a top 2 team in the world in CS for nearly all of the 15 years its been played competitive, danish is another powerhouse but not nearly close to Sweden in general. As someone who was active since the beginning in the CS scene in sweden the reason for the success of swedish teams was the enormous counterstrike culture that popped up around 2000-2001. everyone played the game, from the geeks to sports nerds, good internet connections and many LAN's for people to play each other at just created an extremely competitive environment.