Even a success rate of 50% would be startling. I don't believe it.

Which is ironic, because the Wikipedia page you just linked to says that "95% of former smokers who had been abstinent for 1–10 years had made an unassisted last quit attempt", with the most frequent method of unassisted quitting being "cold turkey", about which it was said that:

53% of the ex-smokers said that it was "not at all difficult" to stop

Of course, the page also says that lots of people don't successfully quit, which isn't incompatible with what thomblake says. Among people who are able to congruently decide to become non-smokers, it's apparently one of the easiest and most successful ways to do it.

It's just that not everybody can decide to be a non-smoker, or that it occurs to them to do so.

Anecdotally, my wife said that she'd "quit smoking" several times prior, each time for extrinsic reasons (e.g. dating a guy who didn't smoke, etc.). When she "became a non-smoker" instead (as she calls it), she did it for her own reasons. She says that as soon as she came to the conclusion that she needed to stop for good, she decided that "quitting smoking" wasn't good enough to do the job, and that she would have to become a non-smoker instead. (That was over 20 years ago, fwiw.)

I'm not sure how you'd go about prescribing that people do this: either they have an intrinsic desire to do it or not. You can certainly encourage and assist, but intrinsic motivation is, well, intrinsic. It's rather difficult to decide on purpose to do something of your own free will, if you're really trying to do it because of some extrinsic reason. ;-)