Makes for a boring Amsterdam... I can see historic cities all over Europe, and there are parts of the low countries a lot prettier than AMS. There's a lot less reason to visit Amsterdam the more tame it becomes.

I suspect Hamburg becomes more popular, with its much larger but (previously) more tame red-light district.

It's so necessary. In the last several years, the red light district and the coffeeshops have really multiplied and spread outside their historic boundaries. At the same time, they've become increasingly centralized and internationalized - i.e., controlled by international sex and drug traffickers. The mayors aren't trying to do away with the trade at all, just bring it under control and pare it back to the point where it doesn't overwhelm the city. And pretty much all of the Netherlands is behind them.

Still not convinced? Imagine that Times Square had never been Guiliani-ized in the 1980s, and that the peep shows and massage parlors had instead multiplied and spread all the way down to Herald Square by today. Then add drugs to the mix. (Or for a more DC-centric analogy, imagine that the joys of Logan Circle in the 80s were still there, had spread out to Dupont and as far south as K Street, and had become organized by gangs.)