Do people smoke because of packaging? Obviously not. People smoke for many reasons. It could be due to stress or habit. Of course, addiction is included.
I suspect this whole idea of plain packs will just push more sales for the tobacco companies. In the US, it has shown over and over again that anti-smoking policies just encourage smokers to smoke more.
Check out my post at http://www.scottmitchellrosenberg.com/plain-pack-help-quit-smoking/ to read my other views.