I feel like both sides of the nicotine/cigarette debate don't focus enough on addiction. One side on the beginning of the addiction cycle for youth and the other side on the consequences for current addicts.
A big issue with any sort of nicotine reduction policy is that public perceptions of safer nicotine alternatives are pretty confused. Roughly a third of people think e-cigarettes are as harmful as regular combustible cigarettes. A quarter don't know. Only about a third correctly think they are less harmful. That unfortunately reduces their value as a harm reduction tool for current addicts.
And nicotine replacement therapies are not as accessible and varied as they could be. They also just don't have nearly the same effectiveness at sustaining use as cigarettes due to the lack of the other addictive and mood-altering chemicals.
So unless there are gradual phaseouts, you could be leaving current addicts in a bad situation where they just smoke more cigarettes or go to the black market.
It might make more sense to use harm-adjusted taxation for the various nicotine products to shift consumers on price to the safer nicotine options away from more harmful combustibles.