Their online tech, bundled apps, and the Aqua GUI style don't need to be opened up for macOS* itself + the Kits + Finder to be open sourced.
If people could reliably and legally install it on any PC they want it could still cut into Windows' share a lot more than it currently can.
It's not hard to imagine that before long, enterprising people will release custom "distros" of it, say with an up-to-date OpenGL, or even a Wine/DirectX emulation layer baked in so we can just double-click on any .exe and have it run natively.
* As I'm assuming/hoping it's going to be called starting June 13. They could open source "OS X" while keeping the "macOS" brandname for themselves.
My point is that Apple has no interest in doing any of that.
> If people could reliably and legally install it on any PC they want it could still cut into Windows' share a lot more than it currently can.
But Apple would lose a huge amount of money on hardware sales, which is where they make their money. Apple even tried an approved clones program in the 90s, it was a miserable failure and one of the first things Jobs did on his return was kill it.
> It's not hard to imagine that before long, enterprising people will release custom "distros" of it
Which Apple really wouldn't want. One of the selling points of OS X is the lack of variation in both software and hardware.
You may be right, I'm not sure. Personally, I would only want for my custom desktop. As for laptops, I've looked at other vendors and as nice as the new XPS 15 looks and has a type C connector that could be used for external GPU, I can't help but remember the XPS 15 that I used as my main for a year where within that time, the wifi became hosed and the battery required replacing. Forget that. As far as laptops, the MBP I bought after that laptop is the only one I've had any real confidence in.
As such, waiting for a new 15 MBP (current is 13) with Type C connector(s) and then will upgrade.
OSX being available on non-Apple hardware would just make it where my desktop and laptop could play nicely together.
I completely agree with all your points, but to be fair iOS dominates desktop Mac in terms of revenue to begin with ($51B iPhone + $7B iPad vs. $7B Mac). That's reflected in the fact that Apple continues to open source XNU on desktop (granted, not in anywhere near approaching an open-process, or complete, manner) but not on mobile. Apple has historically been more willing to open source things they don't make money on (e.g. LLVM and Swift). Seven billion dollars is a far cry from zero revenue, but it's an interesting trend nonetheless.
Many people who like Macs will continue to buy Macs even if OS X was freely available on other PCs, and OS X would continue to indirectly generate revenue for Apple even after it were open-sourced:
For one, many more people will have access to the Mac App Store and the iBook Store, leading to increased sales for apps like Final Cut and Logic. There'll be many more potential customers for their iCloud Drive storage plans. Last but not least, it will drastically lower barriers for iOS/tvOS/watchOS development as people will be able to develop on any PC they want, not to mention it would increase the pool of people making native Mac apps as well.
Apple can still differentiate Macs through their hardware, things like their pressure-sensitive trackpads, form factor and by keeping bundled apps (like Photos and stuff) closed-source and exclusive to Macs.
But it's not open source in the way Swift is. Apple doesn't have a git repo or something for Darwin. In essence, you only get the "tags". They don't take pull requests, you need a Dev account to post bug reports, etc.
It feels a bit dangerous to claim that the only True Open Source projects are the ones hosted on Github and Github alone. Just because the source code isn't released using your favourite version control system doesn't mean it's not "open-source." The code is available and yours to use.
I agree that Apple's darwin release doesn't have much of an open-source community around it.