Many smokers find it hard to enjoy themselves if they go for an hour or two without smoking. That's not to say they can't go without smoking, but they don't enjoy themselves.
People who go to bars and fancy restaurants generally do so for the purpose of enjoying themselves. Few people will go to a restaurant to spend $30 or more on a meal they know they're not going to enjoy.
I've noticed that many fast food places around me are completely non-smoking, and suspect there are four reasons: (1) smokers can generally be in and out quickly enough that not smoking for the brief time in-between isn't a problem; (2) smokers who don't want to stop smoking long enough to eat can get food to-go; (3) smokers who don't want to stop smoking, even for a moment, can use the drive-through; (4) many people who go to fast-food restaurants aren't particularly concerned about enjoyment.
If bars were allowed to let people have beverages to-go, they might not be hurt too seriously by a smoking ban. Unless a bar has an attached beer garden which allows smoking, however, they generally can't.
Bingo. The "enjoyment" of the dining experience is the argument advanced by both sides. Neither ardent smoker nor non-smoker apparently can enjoy their meal in the environment preferred by the other. So, what should be done?
For the person who prefers liberty to tyranny, the answer is simple. Where you are the host, you set the rules. Where you are the guest, you abide the rules of the host or you remove yourself as a guest.
Under the capitalist system we have buyers and sellers. Buyers and sellers implies the existence of private property. If you can't figure who is the host and who is the guest, it is because you lack an understanding of liberty and property.