Think: smartphones (Android), routers, smarthome/IoT devices, other embedded devices.
Linux developers made an intentional decision to stick with GPLv2 and to remove the "or later version" option, so you can't include it into GPLv3 projects as you can with most other GPLv2 software.
GPLv3 avoidance is why Apple ships ancient versions of Rsync, Bash and Make on its current OSes instead of the current versions, and replaced Samba with its own inferior SMB service.
It only governs distribution and especially prevents distributors from locking their users in, and from placing restrictions on their users' use of the software.
If software is GPLv2, it's penalized relative to more permissive options when it comes to picking one. In practice it means that it's avoided unless it's "too big to avoid", or because the very nature of what you're doing requires it - this is the case for e.g. Linux and R.
If software is GPLv3, it's considered radioactive and is avoided at all costs, even if it means rewriting large amounts of code from scratch.
The GPL licensed git.
If I'm forced to use MacOS, I'm fine installing git, GNU make or whatever I want for myself. But I don't see any downsides in Apple being unable to distribute those applications together with their OS.
Why would they do that? I didn't, because macOS ships with version 2.39.5 as /usr/bin/git. You're free to upgrade to a newer version, of course, but the included one is recent enough for most uses.
