True, but the US actually has one of the lower smoking rates in the first world. Nearly twice as many people smoke in Japan than in the US, for example.What is the % of persons having sugar (diabetes) in your country (USA)? I think it is around 8% (correct if wrong). And google says "obesity cuts 14 years from your life expectancy". And also cigarettes play role to some extent I guess.
I agree that exceeding 90-100 routinely is a way off. The last 100 years has mostly been about eliminating a lot of the easy killers, reducing infant mortality, etc. The next step is to improve people's lifestyles. But even if we were all marathon-running macrobiotic diners, there are still fundamental limits. Of the three causes of death, you can perhaps surmount disease and reduce trauma, but aging itself is the cause of many different things and we don't even have a solution for one of them.
Various scientists have said that immortality is an "engineering problem" rather than a "science problem". Even if that is not over-optimistic, there are plenty of engineering problems that have taken a looooong time to solve. Fusion energy would be a good example.
I'll go out on a limb and say the vast majority of people reading this post will die before they're 100.