I agree, actually.
I don't smoke myself, but have found myself at times with these same (or at least likewise) thoughts. There have been numerous nights I've just gone out and sat down somewhere in the middle of nowhere, looking up at the stars and just thinking about how... today I am.. Tomorrow I might not be. And such.

I believe that smoking - and the addiction to it - is mostly because you allow yourself to free your mind for that five minutes, and just let go of everything around you. But I believe you could train yourself to do the exact same thing with something other than actually smoking, hence replacing one habit with another if desired.