[DaiPlusPlus]

Apple pretty much said that Cocoa would be the basis for all future work they do on Mac OS X since 2001, and they've continually improved it, such as adding new widgets, adding functionality to existing widgets, high-DPI support, and so on. I see there's a lot of DRY (Don't Repeat Yourself) going on: there is only one GUI platform and UI toolkit for macOS: Cocoa. While the groundwork isn't new it is kept up-to-date.

Compared to Windows where the "original" widget-toolkit (Window classes and the Common Control library) haven't been significantly updated since Windows XP - Wndows 7 did add some new controls, but they aren't exactly easy to use unless you're already a very experienced C++ Win32 GUI developer.

The old low-entry-barrier dev story was VB6, which had a mix of Common Controls and ActiveX reimplementations, then it moved over to VB.NET and WinForms, which is a wrapper around the same - but the last significant update to WinForms was in .NET 2.0 in 2005 - Microsoft recently announced that they would not be adding true high-DPI support to WinForms, advising desktop app developers to use WPF or UWP instead - and therein lies a problem: WPF and UWP are both completely separate UI and application stacks. WPF is not perfect and like WinForms, hasn't seen much of an update for a while (it still runs on DirectX 9) and UWP is just confusing: it's arbitrarily limited to only run in a restricted sandbox environment, the standard widget library is very anemic (e.g. still no tree-view!) and it shares nothing in common with the rest of the entire Windows ecosystem.

If you want to write a "real" Win32 desktop application you're best-off sticking with MFC, but there's so much legwork that's necessary, and legacy cruft (I swear the MFC codebase is still C++89 compatible) it just doesn't make sense for small applications, especially line-of-business systems that face constant changes, to be built with it. Compare with Cocoa on macOS where everything: from Microsoft Office and Adobe Photoshop, to the built-in Jigsaw Puzzle mini-game, is all built with the same framework.