Those might need the end of life pain management one day. Its what makes it so vicious. They are in no position to think the horrible consequences through.
edit: Lets lot sugarcoat this. This is not a new idea. If you push this on somebody, you might as well torture them to death yourself. Its that bad of an idea and your motivation doesnt change the outcome.
There are a whole lot of worse fates then being an addict and being in excruciating pain because of a preventable lack of end of life pain meds is one of them. You can look around, large parts of the world are doomed to this because of a merciless crusade against pain meds by people who couldnt deal with their loved ones choosing a drug. And i will be damned if its because nobody wanted to hurt their feelings by explaining this to them.
That is a caricature. You can invest in naloxon if you are worried about that. Or better yet, go the route of Switzerland and provide safer alternatives for life long addicts. It does absolute wonders for their quality of life.
The crux just is, that in this discussion, sober is the most important metric for a lot of people. Overlooking not just the end of life problems, but the simple truth that without drugs, a lot of those addicts would have killed themselves already. Drugs arent just a fly trap for the careless, they are a haven in the storm for the desperate. A shitty haven for sure, but in some situations less bad then the alternative. That distinction explains a lot of why all the warnings get ignored and all of the "education" on the topic finds only deaf ears.