Many Forums members already have a lifetime supply on hand even if they Iive to an unusually advanced age. I would say a majority could coast on what they have for ten years, and longer if they cut down on their daily use.
My stash is far from huge, extremely modest by Forums standards, but I'm good for a decade anyway. And of course, I keep buying a few baggies or tins from time to time. Mostly, the membership here that worries about this is unlikely to be much affected by it. Young newbies might have to respond, on the supposition that they'll keep smoking, if that seems probable.