There is no doubt that the smoking ban has contributed to the closure of so many pubs.   The last statistics I heard put the closures in England at 14 per week. Pubs need to make money and a lot of their core customers were smokers.
This will be vigorously denied by the anti smoking brigade but the timing cannot be a coincidence.
I for one have given up visiting folk clubs because, although I can accept no smoking rules in concert venues, I refuse to stand outside in the cold in order to smoke. The only time I go into a pub now is in order to eat. Having done so, I leave and visit a fellow smoker's house fo a drink or invite friends to my house.
Anti smoking zealots have made a major contribution to the demise of the community pub. It is hypocrisy to try to blame the breweries etc.