When Lee Hazlewood left the USA to keep his son out of the draft he went to Sweden and produced amazing albums (Cowboy in Sweden and Requiem for An Almost Lady.)
There is something about Sweden that produces not just great music but well produced music. This might have something to do with it: "On the most basic level, municipal music schools increased the odds that Swedes would discover their talents, while also giving the country an unusually music-literate domestic audience."
I couldn't tell you (nor care to know) about the Swedish input on Katy Perry to Pitbull but I've been a fan of some awesome swedish acts for a while: Komeda, The Concretes and Taken By Trees (former Concretes singer.) A guy at work swears by The Hellacopters as well.
So there's not just the money-making-shit that the articles point out (Note: I like Abba but hate the music style it spawned.)
Just in terms of production check out this cover of Smells Like Teen Spirit: https://www.youtube.com/watch?v=JjBV12gKofE he makes it his own.