Now, the proportion of people who still take up smoking today do so in spite of all this, which is probably down to them having various specific user profiles that are unaffected by this (IE they live in communities/work jobs where its ubiquitous or are huge James Dean fans).
For gambling, you could possibly go a long way with awareness and labelling, but I think an issue is that gambling is a lot less visible than smoking. Nobody can smell that you popped outside to blow your paycheck on tonight's game. Making gambling deeply uncool might make some people not take it up, but most of the existing addicts would likely carry on in secret. They're already commonly hiding their losses from spouses and friends, so what's one more layer of secrecy?
At any rate, what worked for smoking wasn't making smokers quit, but making fewer and fewer kids start doing it, so making it a pain in the ass to place your first bet might help.
Gambling in some of those same countries is now very aggressively advertised.