I don’t think this is it. A lot of the unhoused in Seattle are locals or in state, and many of the out of state are from neighboring states such as Idaho or other West Coast states.

Rather I think the problem is that half assed decriminalization efforts simply aren’t enough and that drug overdose has become a much more severe issue because of the opioid epidemic and the proliferation of fentanyl. What needs to happen for decriminalization to work is much better social support for addicts, including safe use sites staffed with nurses, free health care for addicts including detox hospitalization and substance abuse treatments, social housing including housing specifically for recovering addicts and active addicts. In addition full legalization and regulated drug markets (preferably via pharmacies with a strict non-profit motive) wouldn’t hurt either.

What Seattle has done is basically just decriminalization without any of the support needed to go with it. Yes we support addicts and spend a lot of money on their care, however these are all suffering from austerity and are often just post-hoc measures (which often cost more in the long run).