I think that it's often underestimated just how much of what made/makes OS X/macOS good is actually in AppKit and the various other frameworks it's used with. P

I think that it's often underestimated just how much of what made/makes OS X/macOS good is actually in AppKit and the various other frameworks it's used with. Parts of it are a little aged compared to something that's received more attention in the past decade (like UIKit), but it still does a LOT of heavy lifting and makes developing a polished, capable desktop app much less of a headache. In writing apps with other desktop UI frameworks, it's become evident just how much AppKit does well that many frameworks barely do or don't offer at all. Sometimes it's even really basic things, like how WinUI somehow has no first-party tableview despite that being one of the most fundamental desktop widgets. Cross-platform AppKit would be a dream setup.