I'm confused by your comments, and am asking for clarification of your perspective. What exactly is your point?
While 20% of the population still smokes, the incidence rate has hugely decreased over time[0].
According to the CDC, in 1965, ~43% of the population smoked. In 2011, it was just under 20%, with a goal of 12% by 2020.
Transparent labeling, increased regulation and awareness, plus general advances in understanding the consequences of smoking have had a massive effect on the rates of smoking. It's not perfect, but a similar reduction in obesity over the next 50 years would be an incredible accomplishment.
Now if only we could tackle that burgeoning mental health problem...
[0] - http://www.cdc.gov/tobacco/data_statistics/tables/trends/cig...