If the volume of people at traditional resturants on most nights and the amount of people in the Best Buy parking lot on a Saturday are any indication, I'd say no.Does the drop off in business have anything to do with the economic downturn?
The places that are hurting due to the smoking ban are establishments with niche clintel. The local watering hole. The local bowling alley. The local Moose lodge. The folks who freqent those places are there for a specific set of activities. Take away one of those reasons to go and apparently the alure is not there. You can't say the smoking ban hasn't hurt Applebees because people usually don't go their specifically to smoke. If their business goes up/down it's likely got little to do with the ban (it might tick upward from those who hadn't gone there because of the smoke but I haven't heard of a tidal wave of new business at traditional resturants because they are now smokefree). However, for an establisment where smoking is part of the reason to go there (i.e. sneak to the corner tavern for a cold one, hang out with the buds and grab a couple of smokes), it's pretty obvious what the reason for the downturn is.
But not to worry. Those who love to legislate their way to nirvana know whats better for you than you do.