To me, it just depends on whether or not you really want to. I know a few people who don't seem as though they truly want to stop.
I feel it's purely mind over matter and if you possess the will, determination and no longer the NEED to smoke, you can then overcome it and quit. It's probably just not that simple but what other way can you stop, if you don't use those patches or chew the gum (if indeed those actually work) ?.. I think you should quit slowly, meaning that you progressively smoke less and less in a day, until you can find that you just don't need it anymore.