Not sure if it is that easy to just built housing for everybody (excluding those 2 people in the entirety of NL who choose to be fully homeless). At least speaking from a NL point of view. If you have no income and you don't have assets you get money and the ability to rent something. It isn't a lot of money, but it should be enough to survive. This is sayiong that if you are actually Dutch and not somebody who came from another country without going through the system to get either asylum or become Dutch.

However, it is really hard to find housing for people in general. Even harder if you earn just enough to not have any rights for social security.

I believe the people who want to do drugs here in NL have the ability to do so in coffee shops (the drug serving once)