I suspect part of this is because smokers, generally, don't always live long enough to actually get cancer, and statistically their year-over-year cancer risk d

I suspect part of this is because smokers, generally, don't always live long enough to actually get cancer, and statistically their year-over-year cancer risk drops to the same as the general population when they do quit. However, COPD, once established, is irreversible. My dad was a long time smoker and it was COPD that eventually got him. He battled it for years after he quit.