I should have been more clear: Apple has and continues to ship GPLv2 software but not GPLv3, since one interpretation of that license is that by including GPLv3 code in macOS, they’d be required to make the source code to at least the entire Darwin (the Unix layer underneath the GUI) operating system available, which is something they probably don’t want to do.
Which is why GNU’s core utilities don’t ship in macOS and why the outdated Bash 3.2 (GPLv2) still ships in the latest versions of macOS.
It’s also why ZSH, which uses a variation of the MIT license, is now the default shell when Bash was the default for many years.
> Darwin (the Unix layer underneath the GUI) operating system available, which is something they probably don’t want to do.
Darwin is open source, and Apple did make Darwin available[1][2], but the issues are it takes some skill, experience, and understanding to put it all together and build it, and many parts have become closed source since Apple first released. Also, there are basically no drivers for anything.
At least two projects derived from it, making it far easier to install and boot, OpenDarwin and PureDarwin. PureDarwin[3] had a couple of bootable releases, but I haven't heard much about it since their last release years ago, but their site says they've been working on drivers and a modified XNU to work without Apple's closed source portions.
IIRC, way back during the end of PPC, I was able to install and boot Darwin CLI on an x86 (probably 486 or Pentium something), but without any drivers, I couldn't do anything with it other than boot it and explore the filesystem. I couldn't even get it to network, so I couldn't install MacPorts, lost interest pretty quickly. It looked exactly like booting Mac OS X without Quartz, Apple's pretty command line.
But the PureDarwin release had X11, and by the screenshots, looked pretty neat. I intended to try PureDarwin's Xmas release in a vm back in the late 2000s, but I was jerked around a lot back then with living arrangements and never got back around to it. PureDarwin's later releases had a lot more functionality.
