Make it like Vampirism or Corprus in Morrowind, once cured, can't be achieved, so if you by mistake took one dose of Jet and then discovered it's forever, you getting Jet Antidote by some way, may be even not repeatable quest, and then, after taking this antidote it cures your Jet addiction and makes taking Jet in future has no effect on you, so you cutting off your character from this drug forever, but also don't suffer from addiction.
This way Antidote will be useless for Jet builds and useful for those, who didn't know about addiction/took it by mistake. That's the point of all these threads about Jet. And make it not rare, anyway it'll be used only once per character per character's life. Available as BPs and at doctors.
But then there could be threads like "I accidentally took Jet antidote! And now my Jet build is screwed!" and there will be "Deal with it."

And someone will propose "Anti-Jet-Antidote cure!" and "Anti-Anti-Jet-Antidote".
In any way "Deal with it" suits every case. And I find this suggestion the best as it's already implemented (nothing). Using Jet is like losing virginity and fine as it is. You shouldn't be able to become virgin again.