If I remember correctly, cold turkey has worse rates for initial quitting but the lowest rates of people returning to smoking for those who "made it"

IIRC it has to do with the anguish of quitting - if you went through the difficulty and pain of quitting cold turkey you probably don't want that to be for nothing

Sunk cost strikes again? This time for good.

I wouldn't say sunk cost so much as you now have a better understanding of what the price is now that you have paid it once.

Cold turkey is how my dad did it after 40 years of 2 packs a day, unfiltered. He went through a couple weeks of hell, but as far as I know he hasn't smoked in 21 years.

I have worked with quite a few elderly people, and I've heard many stories of people just quitting cold turkey after many years of smoking, as soon as the catastrophic health effects became common knowledge.

I think the older generation is just generally more accepting of discomfort than todays cream-puffs.

I remember reading a study done in the UK that said the exact opposite. 70% of people going cold-turkey were able to quit for good. They compared it to the number of people quitting using helping substitutes (like patches, ecigs and whatnot) where the success rate was way lower.