My immediate thought is that smoking overall is falling and falling, so maybe advertising does more than shift brand loyalty of existing customers.
Semi-related: I was pretty convinced that smoking was at maybe 5% in Canada based on my observation that almost nobody where I've worked and gone to school smoked. Turns out it's closer to 25%, which was shocking. I came to realise that smoking must be very very concentrated among specific demographics as to insulate me from it. Got me thinking about how my perception of advertising for smoking may also be very very off.