It seems more plausible (to me) that this is the result of the cultural 'quarantine' of smoking and not the efficacy of the "don't smoke" programs in schools per se. The entertainment industry in the US aggressively committed to not showing cigarettes in a cool or positive light, and to me this seems way more likely to have driven these reductions in youth smoking. In the 80s pretty much any person a 13 year old would call 'cool' could be seen smoking somewhere. Now media uses cigarettes to either indicate that a movie is happening in the past or that a character is self-destructive. With the cultural cachet gone, or greatly reduced, I think what you're seeing is mostly 'background' smoking rates: kids smoking specifically for the effects of nicotine, or because it's a taboo-breaking behavior. Not because their parents and every celebrity smoke. This dynamic also explains the rise of e-cigs, IMO. Kids love streamers and influencers, and streamers and influencers vape nic. Now kids vape nic.