I'm not 100% convinced that the smoking ban has diminished pub attendance....not THAT much.
In my opinion it is the exhorbitant price of drinks, compared to those massively discounted in supermarkets.
In ''my day'' we went out for a beer and chat up the opposite sex because we had a gang of mates who we could meet, AND we had quite a bit of cash.
These days kids are by and large skint, and even those who are not would rather meet their mates in cyber-world. (Facebook etc)