A lot of genres are like that. For example there are a ton of Swedish Melodic Death Metal bands, as the style was pionered here. Hardstyle was big in Holland + Australia, House originated in America but Americans didn't know what to do with it so Holland and Sweden took over, Dubstep is from London so you have tons of UK producers, Germans love Industrial so they have a lot of different artists in the sub-genres, etc.

Local music scenes usually spawn many of the artists you hear, a lot of them are friends too.