I think vaping is a viable replacement, honestly. I  used to say I was a stress smoker and I would never "Really" quit, but that seems to be going away. I will say for me, substitution is a viable deal, when I quit caffeine I like always drank decaf and was like "who cares." When my diet pepsi addiction has to be addressed you can for sure bet I will switch to the (healthier unsweetened, maybe healthier) sparkling water, and not regret it either.  If you think I'd t try to go for lovely plain water, you'd be crazy.  
So substitution tends  to work for me. I think it's why it works for a lot of vapers. I SURE craved cigs in the beginning  but no longer really do.
My dad, who smoked in his youth, and has had a heart attack still states it is (and was) the hardest thing EVER. He used to travel on planes and think (this was back when you could smoke on them) "How would I feel if the plane went down and I HAD not smoked, etc.) He relapsed with the alcoholic new wife, and quit a couple of times.  He STILL complained of wanting to smoke so much sometimes, only the  hell of knowing he would  have to quit, like, stopped him.
I think some smokers are like that, and some very much aren't. I am though sometimes the only  thing which got me through the  pregnancy was like, imagining ahead to  the age I could safely smoke, i.e in the nursing home or something.  I knew I wouldn't LAST that long, but eh.
Anna