I know several people (including family members) who spent several decades "trying" to quit smoking, but "couldn't"... until they started having health problems and a doctor told them very clearly and in a serious tone that if they didn't quit, they would die.

At that point, they quit literally overnight and never went back. And I'm using "literally" literally here.

So yes, I know it's hard, but I'm pretty sure people who don't manage to quit just don't want to quit hard enough. They "want" to in the same sense that I want to learn martial arts: I've always thought that it would be great to master a martial art, and sometimes fantasize with it, but I know fully well that I'm never going to do it because I'm not willing to do what it takes (the time, the discipline, receiving blows, etc.)

In other words, I don't think wanting to snap a finger and magically never feel like smoking anymore qualifies as wanting to quit smoking.