No, smoking reductions absolutely are 100% definitely due to government intervention, and it's extremely instructive and important that that is so. Much of the initial critical medical research came from Britain, and Britain has a national health service; it's socialised medicine.
And the thing that finally has killed smoking as a thing in the West was passive smoking.
Passive smoking was something that was (in a loose sense) invented by government health agencies, specifically to kill smoking.
By invented, I don't mean that that it's not true that passive smoking is harmful- that certainly is true, it is harmful carcinogens, no, I mean the concept that passive smoking is harmful... AND SO it cannot be done in places of work.
That really, really put the kibosh on smoking.
And THAT's a regulation; it was specifically THAT regulation that enormously diminished smoking.
Before that regulation, smoking was hanging right on in there, the smoking companies were able to pretend that smoking wasn't extremely highly addictive, and that it was 'relaxing' or some such bullshit.
It really was that way around. And that's normal. Governments have a responsibility and genuinely are best placed to enforce regulations with respect to safety and fraud. Really, the tobacco companies were enforcing a fraud on the population that cigarettes are safe. Even the smokers didn't really believe it, but they were addicted.
I am actually pretty libertarian, but when right-libertarians try to argue that it's personal responsibility whether or not there's sugars of lead in my wine or not; I can only laugh at them and their efforts to explain how I could ever realistically test the products I buy. Governments of course don't routinely test products, but they do do random checks. And that smoking was morally unacceptable came from governments.