One reason they don't ban them at least in the US is the amount of tax dollars smoking brings in. On one hand they tell people not to smoke on the other hand they are depend on the tax dollars from smokers. Also smokers don't live as long as non-smoker. That means less social security being paid out. The government saves money. I know people say that smokers run up health cost because of the illnesses they contract but that is at the end of their life and the cost of heathcare go up for most people the last few years of their life.
If the government is going to start continue to baby sit us then I think they should outlaw most of the breakast cereals, soft drinks with sugar and most fast food. Have you noticed all overweight children and adults there are these days? These people are also shortening their lives with the poor choices they make but do you really want the gov. making those choices for them or for you?