pretty easy. governments took an oppositional attitude to it. they made it easier to get information about the cons and (at least as importantly) harder to get information about the pros. amongst other things.

saying that there's a "lack of prohibition" in cigarettes is kinda missing the point. the fact that one particular approach to discouraging a disapproved substance failed, doesn't mean another approach isn't being tried and - as you note - even successfully.

Sorry, I'm not quite sure if you're in agreement or not.

The claim was that humans need to be protected from themselves (in the context of the GP comment, this would mean a ban).

I meant to imply that since smoking rates declined steadily without a ban, the claim that prohibition is the correct answer because we humans can't stop trading short term pleasure for long term pain seems dubious.

That's even without considering our extensive experience with what happens when we prohibit substances which sellers want to sell and still not insignificant parts of the population want to buy.

i think we agree on the facts and disagree on the interpretation. smoking rates have gone down because the goverment has tried to eradicate it. so far, without a ban. it has been pretty successful. this doesn't say much about the success of a ban, but a lot about the government's ability to protect us from ourself.

the effectiveness of bans is far from univocal (which you see to admit by using a condition which would let you move the goalposts whenever i find a counter argument), and a ban on new nicotine products today would be completely different from the ban on alcohol in 1920s America. success doesn't have to be 100% for it to be good policy either, as the ban on murder shows.

I think the difference here is that I don't see education and internalising costs as protecting us from ourselves in the sense given by the OP (that even knowing perfectly the costs, we humans will still make the wrong decision and so need further protection from ourselves).

The effectiveness of the campaigns shows that given enough information we can in fact change our behaviours without needing to resort to prohibition, which is probably how I should have phrased my first response and skipped all of the rhetoric.

Purchasing cigarettes as a minor was prohibited in the late 80s.