And also pollution. If it were possible to prove that the cancer a person has can be traced back to pollutants released by a specific company, then there would be even more lawsuits. But since that isn't possible, air pollution continues.
I'm frankly surprised that huge polluters in America are not already being sued by environmental groups and common people. But as far as your argument goes, it does not stand up to scrutiny. You don't buy air, and there is no distributor of air. We all share it, and are collectively responsible for it. Also, the chemicals in it are not addictive and make you search them out to get your fix, only to get cancer later.
If companies were bottling air that contained addictive carcinogens for you to breathe, then they should be sued. As it stands, you can't prove which pollutant from which company is harming you, so they get off scott free... unless of course the government comes down on them, which, IMO, they should.