Really? Did the start of a long recession just before the smoking ban started have nothing to do with falling pub attendance, except for discount outlets like Wetherspoons. You also have to pretend JDW didn't start making *more* money months before the official ban when they banned smoking early, my favourite sight of the time was a builder being physically thrown out of a pub by his workmates as he tried lighting up at the bar.
We'll never be able to pin down what, if any, damage the smoking ban did. It did break the decades long fight by pubs&bars to do avoid doing anything meaningful about the problem. Offered a deal - provide a moderate number of smoke free rooms spread across geographical areas - and there would be no need for a ban. They got nowhere near and it became very clear from trade publications the belief was the gov would back down. That's how we got today's ban.
Apart from losing pub gardens to smokers it's been good. Just wish I had less other ways to spend my disposable income, the real reason pubs struggle to get us into them.