alt Hacker NewsWine has been going for a very long time - since 1993.
When it started Windows was a lot smaller, so getting Windows 3.1 programs working was probably enough.
There's too much history to cover in a quick comment.
Wine has a lots of things that help - the compatibility database https://appdb.winehq.org/ is a good place for people to submit info on apps for instance, there's also a big test suite that runs against Windows + Wine.
Both of these have been around since the 1990s - Darling is at an earlier stage, but once GUI apps run better both of those are good ideas to adopt.
I think Darling probably needs more people working on it.
The whole are of Metal on Vulkan looks interesting https://github.com/darlinghq/darling/issues/390#issuecomment...
Also, Mac is a moving target. Each year, there is a new version that is basically its own little snowflake, with older things deprecated and newer things added.
Windows 11 will still run Windows apps from Windows 3.1, because they have a backwards compatibility effort that Apple eschewed.
Now that makes it more complex to emulate all the features, but the core features used by most programs get emulated, and then just add features for specific programs to get them to work. And games tend to use core features and DirectX or OpenGL, mostly, whereas productivity apps and other things can do lots of weird things that are non-standard.
For Mac OS X, you really need to handle each versioon of Mac OS X. There are some core features that may work across versions, and some features that are available only on certain versions, then some features that are unique.