Cocoa - I think the reverse it more beneficial... something for Wine for Mac. Porting Cocoa to Windows could be just a difficult as porting WinAPI/WINE to Mac. (Aside from perhaps patent/copyright issues.) IMHO a Mac that is able to run more applications in its native system is far better than making an alternative OS to the Mac to be able to do more. Err... I mean, when you can run Windows only program on OSX, it becomes another reason/motive for people to get a Mac; whereas if Windows can run Apple-only program, would make one less reason to get a Mac, since you don't need a Mac to run Mac programs anymore. Won't do much harm to Mac users, but certainly doesn't do any good for it neither.
Not necessarily.
First of all, porting Cocoa to Windows would be a lot easier than something like WINE, because the WINE folks need to first reverse-engineer Microsoft's APIs. Apple has full access to Cocoa, obviously, so that's not an issue for them.
Now, what would it do for Mac users? Well, it would give developers a good way to make cross-platform apps. Currently, there are no powerful, flexible cross-platform APIs that don't produce hackish/slow/bloated/fugly apps on some or all platforms. Even some of the best cross-platform apps
feel like cross-platform apps. A lot of new Mac users don't care, and love their Firefoxes and their VLCs to death, but apps like those — as useful as they are — compromise the entire Mac experience, because they're made to be cross-platform first and foremost. Imagine if Firefox were written in Cocoa. Ahh, I can dream...
This would make Cocoa appealing to currently Windows-only developers, which would in turn mean more cross-platform programs (that Don't Suck™
. No level of Windows support is going to make Windows apps run as well as Mac apps on OS X. Ever. In fact, that could discourage Windows developers from bothering with Mac ports at all. Even as things are now, I've had developers tell me "well, you can run it on Macs if you use your Windows partition". (Yes, they believe Windows apps are "Mac compatible" because they run on Mac hardware.) Heck, some developers used to use Virtual PC as an excuse! That sentiment will increase with things like the new Parallels or possibly Leopard's Boot Camp. It's likely that anything that makes OS X more compatible with Windows software will result in less Mac software. Apple needs to make it easy to make
real Mac apps, and not just for people who are already Mac fans.
(As you may have noticed, the dynamic here for developers is exactly the opposite as for users. Obviously each group is influenced heavily by the other. It's hard to say what the short-term and long-term effects of a move in either direction would be.)
When a developer has to choose between Windows and Mac, they choose Windows unless they're Mac fans. It's just good business, unfortunately.
Porting Cocoa would make the Mac more appealing even Mac developers. Even for Mac fans, it can be difficult to justify using Cocoa when it basically means ignoring the vast Windows-Linux market. Cocoa for Windows would let Mac developers write awesome Mac apps without sacrificing potential profits and portability.
As a developer myself, I have to say that it sucks to know that when I use Cocoa, I'm making something that's about as non-portable as can be. For some projects, I use other tools, which results in worse Mac apps, but at least I can deploy them on Windows or Linux. It's a tradeoff I really wish I didn't need to make.