Why is this? I don't know. Maybe they put less, er, effort into the OS X driver because of marketshare. Perhaps it was a different set of developers and the Mac developers had some sense. Maybe it's not even possible to create custom-potato-themed printer dialogues for OS X. All I know is that since moving to OS X I've seen far less crapware and whilst you're right that OS X has some UI warts too, I find that it (and the 3rd party software you install) bugs you a hell of a lot less.