Consider all the things out there that you could possibly die from. Smoking is one single thing, that might kill you somewhere down the line, among a million other things that might kill you right this second.
Quitting cigarettes provides the illusion of preventable death. Of course, everybody says they know that they are going to die, but the truth is, nobody really believes it. Eating healthy food, not smoking, getting regular exercise, all of it is with the desire to avoid death, to find a loophole in your contract with the body-bag.
Quitting cigarettes will not guarantee any kind of benefit. The drunk driver who will crash into your car tonight does not care whether or not you smoke.
Quitting will not guarantee an easier death or a longer life
Did you know that there are many illnesses that are not the results of smoking? Old and young sick people will die today who have never so much as inhaled secondhand smoke! And they die too! Some of these illnesses are painful and humiliating and just as ugly as any smoking-related disease.
The best any doctor can tell you is that not-smoking makes it less likely that you will die from certain diseases and conditions. If I don't drive and I avoid roads it makes it less likely that I will not die in an automobile accident. It doesn't make it less likely that I will die in an equally painful way from something else.
Death is, indeed, inevitable
How fascinating is that? Absolute certainty. How many things in human existence are absolutely certain to happen? It's an alien, wholly foreign concept to our imaginations. The thing that is absolutely unavoidable, the experience that is universal. Every risk you avoid, everything you accomplish, every experience you have or don't have, is meaningless in that respect. In eternity it doesn't matter if you die now or in 20 years.