Because the bar business dries up.
In CT, the bar business went to the indian casinos or private clubs (both of which are allowed to have smoking). The rest of the bars saw huge declines in customers and revenues...and tables full of people who stay all night and drink one soda.
For whatever reason, it seems that non-smokers do not drink as much or go to bars as often as smokers.
I think a lot of non smokers drink, they just don't drink in bars.