Shouldn't the decision be up to each restaurant owner and the individual customer? If the restaurant owners are so opposed, then we should allow them to make the decision rather than having mandated by government bans. Using your logic, the effect will be the same.
The fact is that overtime, due to public demand, the number of venues where smoking is permitted will continue to decrease.
This is true from the movie theater to the airplane to the office to the restaurant.
The owners of all the above at first resisted smoking bans but now if bans were lifted very few if any would revert back to the days where smoking would be permitted in their venues.