I think commute distance and terrain/weather are major factors in the lack of lycra you see. While 20+km commutes might be rare in North America too, I think in general regular bike commuters in NA are going much further than most people in Berlin or Amsterdam. Also, while travelling through Belgium, I didn't see too many hills (basically zero) and the weather was quite pleasant (in late August). I'm sure you don't see too many Amsterdam commuters with balaclavas, booties and poagies in December either. Just not necessary. But you'll see that in Canada in December. I still don't understand the appeal of messenger bags for regular commuters though. Seems like mainly a fashion thing.