"Gateway drug theory" has to do with going from one class of drugs to another. That is not what I described. I described usage within a single class of drugs that has to do with chemically addictive properties, strength, and cost dictating the choice of the next drug.
I can see your argument about cost, but I think it ignores that, for instance, tranq is now being used in combination with fent. The reason for that isn't cost, it's entirely strength and chemically addictive properties. I think ignoring those kind of factors falls squarely outside of harm reduction. Where your argument with cost runs foul is in states like California where the legalization and subsequent regulation of the drug shot it's cost up. I'd argue marijuana probably doesn't need that kind of regulation, but chemically addictive substances I think do.
I think you are mischaracterizing the emergence of tranq.
"Xylazine proliferated as a response to the shorter fentanyl highs, with drug sellers using it to extend the high & mimic a traditional heroin experience."
I can see your argument about cost, but I think it ignores that, for instance, tranq is now being used in combination with fent. The reason for that isn't cost, it's entirely strength and chemically addictive properties. I think ignoring those kind of factors falls squarely outside of harm reduction. Where your argument with cost runs foul is in states like California where the legalization and subsequent regulation of the drug shot it's cost up. I'd argue marijuana probably doesn't need that kind of regulation, but chemically addictive substances I think do.