We are all different. I believe some may simply out grow it. Not a conscious effort to quit but something that happens almost on it's own. It gets to a point where the person can't get any more 'mileage' out of it. They have accomplished all they wanted to do with it and it happens outside of their control, the urge just leaves.
The harder you try to snuff something out the harder it is, let it happen naturally.
Some come to a point where they have pushed it as far as it can go, to quote BB King, The Thrill Is Gone. Do I personally know any one like that, no, but I know some who have hinted at it.