[mimsee]

As far as I've understood, the copyleftness of the Wordpress's GPL tainting themes and plugins is or at least has been controversial (I'm not in the WP community, but have read stuff regarding this drama). Wordpress itself uses React and other non-GPL licensed software in the core that yes, may be GPL-compatible but doesn't enforce everything to be GPL'd. When it comes to themes and plugins, I'd consider that userspace, akin to installing Spotify on Ubuntu doesn't make Spotify suddenly GPL'd.

[ThatPlayer]

In Linux, not even in user space: ZFS is developed as a kernel module rather than mainline Linux kernel because of its incompatible with GPL license. Or Nvidia's Linux driver aren't even open sourced. Well AMD has proprietary Linux drivers too, but they have an open sourced one also.

[no92]

Not detracting from the point you're making, but the kernel side for Nvidia drivers for Linux is published on GitHub, by Nvidia. The userspace side is still delivered as pre-compiled binaries, tough.