Can it really be that decoupled from being ready and willing to improve? What's a skill you enjoy doing that you wouldn't want to improve on? I'm thinking a wide area of topics here from cleaning the kitchen to chopping wood to greeting strangers to writing software.

And the original question wasn't even about that, it was about receiving tips/pointers about improving. It doesn't have to be a "never-ending quest" (although isn't life supposed to be just that?). If you're doing some work, and someone points out how you can do it better, he's either wrong, or you refuse to improve... why?

One "why" is simply because people don't actually like doing what they do. They've simply accept it as a worthy tradeoff for the money they get/need. But they're certainly not willing to do any more than the bare minimum.

Do you have other "why's" that I don't see?

I mean sure, if you like chopping wood with a small axe between your toes and someone tells you that holding it properly with your hands would yield a better result then you're fine telling him that you prefer it your way (because you enjoy it), but if you work in a company where you're expected to perform up to a certain level then you can't really use that argument. Feel free to start a competing foot-chopping company!