The desire for nicotine is more likely to lower smoker related disease than the desire to quit
The major decline in smoking and thus smoking related disease will come as a result of the desire for nicotine rather than the desire to quit.
The fiction has been that every smoker wants to quit. The meme has been strong enough that just about every smoker confesses to being a sinner but in their heart of hearts just wants a better way to consume nicotine. And once smokers try these other forms, superior in so many ways (better flavour, easier on the throat and lungs, no smell on the clothing, fewer restricted areas of use), why would they ever go back?
They will stay off cigarettes precisely because they are getting nicotine and in a more pleasurable manner rather than relapsing or failing because they cannot quite get the pleasure of going without.