It is a really fair question. I think there are two lenses. Tobacco does kill people in large numbers although it seems to largely cause issues at the end of their lives. Tobacco also reduces life expectancy, but not as much as opiod users. What I saw said a heavy smoker loses ~13 years and a heroin user ~18 years. Not sure about lighter smokers.

The issue with oxycontin is it helped create a massive generation of addicts who have all sorts of other things associated with them like: rehab, homelessness, and crime. So I'm not sure of the total impact, but likely much higher per person.