Yes, tax revenues from tobacco companies would indeed go down (or perhaps vanish altogether if they went out of business) but the costs to the health care system would go down too - less lung cancer, emphysema, second-hand smoke diseases, etc. - as would other societal costs, e.g. fewer home fires from careless smoking; inefficiencies caused by workers having to take smoke breaks; fewer cigarette butts littering our streets.  Has anyone done a comprehensive cost-benefit analysis of this?