Odds for a never smoker aren't well estimated, but I'd say it's in the single digits. Definitely less than 5%. It depends on one's radon exposure, asbestos exposure, exposure to gas stoves/coal burners, smog pollution, and genetic background. Many lung cancers in non-smokers are driven by single gene alterations (i.e. EGFR, ALK)
Your second question is also interesting. For a nonsmoker to get to 25% lung cancer risk, I guess he/she would have to live past 80, which few people do.
Your statement that we all probably get cancer eventually is mostly true - as we age there is an accumulation of mutations which eventually should cause cancer. Some super-elderly people in their 90s and 100s may have more senescent cells than others, and paradoxically lower their risk of new cancer later in life.
Your second question is also interesting. For a nonsmoker to get to 25% lung cancer risk, I guess he/she would have to live past 80, which few people do.
Your statement that we all probably get cancer eventually is mostly true - as we age there is an accumulation of mutations which eventually should cause cancer. Some super-elderly people in their 90s and 100s may have more senescent cells than others, and paradoxically lower their risk of new cancer later in life.