I think the problem is that people who try to quit smoking are being too extreme.
Nobody would tell someone who is fat to stop eating- you tell them to stop eating too much. Moderation- like Michelle Obama says.
It is really like this with all addictions; people tell you to quit completely instead of a healthy balance, and that is why it cannot succeed.
Like with alcoholism; people tell alcoholics to never drink at all. If someone would tell me to never drink at all, I would slash him with a broken beer bottle. Now imagine if I was an alcoholic and you told me to never drink at all–I’d slash him with 2 broken beer bottles and trample him with an overweight horse.
Speaking of which, that is why horses are not overweight. It is because nobody tells the overweight ones to quit eating completely- so they are able to lose weight healthily.