One other place to pay attention to is Shelton, WA, they have a very interesting communal approach to homelessness and providing services, which has built a strong community that wooed some of my friends to buy and retire in Shelton.
Yes, despite these massive social problems. The economic growth is not caused by drug decriminalization, so I'm not sure why you're loosely associating the two. One uncorrelated bad thing is not seen as the "price" for another uncorrelated good thing.
These kind of efforts take time to take root. As people do things like this in public, that means more opportunity for social services to reach out and try to solve the problem. In 10-15 years you'll see drug usage rates drop as addicts can seek help for their problem without vilification or risk to having their lives destroyed.
Google, Apple, Expedia and Facebook are each building and hiring thousands here in Seattle, our homeless are significantly less aggressive than those I encounter in California.