If we all waited until we could universally eliminate an unethical behavior before we stopped participating in it ourselves, the behavior would never die.

CVS has chosen to stop contributing to a problem, and the behavior of other businesses has no bearing on whether they did the right thing.

Actually there is evidence to the contrary - Cigarette sales fell in the entire state where CVS had a significant market-share, and anti-smoking patch sales increased by 4% in the months following (src: https://www.forbes.com/sites/brucejapsen/2017/02/20/after-cv...)

Granted, it's hard to really know anything, but I'm not entirely sure what you're saying is true. There was probably at least a few people who just said screw it and stopped buying cigarettes because they wanted to quit and needed an impulse. Since their sales actually increased in the years following, and typically cigarettes have ancillary sales, I think at -least- a few people quit due to this move.