https://www.wweek.com/news/state/2023/04/22/economist-magazi...
As I explained in a sibling comment, requiring treatment is not the difference. Very few people who use drugs in Portugal are subject to mandatory drug treatment.
The key difference is that Portugal has a radically different housing policy than Oregon. As of 2019, housing is a formal legal right (and even before 2019, it was much closer to a de facto right than it was to Oregon's current model, which is "if you can't pay for a roof, pitch your tent over there, and hope we don't arrest you for vagrancy").
Most people who use drugs do not meet clinical criteria for addiction, so drug treatment programs are irrelevant and a waste of money for them. For those who do, drug treatment programs are still a waste of money unless they have stable housing, because it is essentially impossible to achieve and maintain sobriety without stable housing.
The big difference between Oregon and the other cities/countries that tried this approach successfully is not diversionary programs - it's housing. In Oregon, housing is not guaranteed, which means any money spent on mandatory treatment programs for people without stable housing is essentially wasted.
Diversionary programs and rehabilitation are a waste of time and money if the recipient does not have guaranteed access to stable housing. It's virtually impossible to achieve and maintain sobriety in those circumstances.