I think there are less streets photographers in Europe for cultural reason.
In America or UK is easy see people shooting in the streets and people don't mind. They ignore each other and don't care what they are doing.
In Germany, France, etc, people check at what you are doing even if you are not doing anything and it may make photographers uncomfortable to have much attention to them.
And people feel uneasy if you just try to have a casual chat while wait the bus in the bus stop. Take their pictures is even worst.
Therefore I believe it is just cultural.
Since I used to do a lot of street photograph in Ireland, I am so used to it that I feel comfortable to do the same in Germany. But even in Ireland where people don't care and even are happy to collaborate it took time to me build confidence to shoot in the streets. If I had to learn and start in German streets I think it would harder to me get confidence.