When this happens the reason 90% of the time is usually not because the program wasn’t working but the opposition to the program has made sure to either gut the funding or put in measures that makes those programs not work (only hiring 2 people to handle all the work or excessive operating requirements.

Cops will fight tooth and nail against social programs because it reduces their budget when problems are solved.

Look up these programs and you will see centrists claiming the progressive program was bad, but never indicate reasons as to why.

In numerous places those efforts have been purposefully sabotaged by police who aren't happy about the loss of court revenues and the eventual cutbacks on police funding for drug prohibition. With them literally refusing to enforce some laws like public intoxication or shooting up heroin in the middle of the street because their more profitable and super easy to get arrests for drug possession laws no longer existed.

Not my area of expertise per se, but the counterargument that I've seen is that the states (e.g. Oregon) that tried it never got the backstops in place to help soften and support the transition (i.e. rehab centers, support programs, social programs). Instead, it was just a hard switch that went expectedly bad.

There's at least a theory that people believe will work that hasn't been correctly implemented yet, but whether or not it's feasible to implement at all, I'm not holding my breath.

Those states half arsed it.

They did the decriminalisation step and then never bothered with the “redirecting savings from policing into services” step.

They also fucked it in other ways.

For an example of where it does work - see Portugal.

Works for Portugal since forever