If you want a point, BSD is probably a better example. Linux is protected by copyright, that's what makes copyleft licenses like GPL possible.
BSD is also protected by copyright, but it matters less for permissive licenses. It still protects attribution (so you can't claim it yours), but it probably would have worked without it, unlike with Linux that is for a big part defined by the "copyleft" protections offered by its licence.
> It still protects attribution (so you can't claim it yours), but it probably would have worked without it, [...]
Well, you could imagine a world that protects the 'moral' rights of authors like attribution, but doesn't otherwise prohibit anyone from duplicating or modifying works.
I don't know about the US but in French "droits d'auteur", moral rights are treated differently from exploitation rights. In particular, they cannot be waived, they cannot be sold, and there is no "work-for-hire". For example, even as an employee, every line of code you write will be yours until you die and nothing can change that. You may not be allowed to do anything with it (for example because the exploitation rights go to your employer), but it is still yours.
So something like the French system minus copyright would approximate the BSD license.
(I was thinking of Germany, which works similarly, if memory serves right. You also cannot release anything you write into the public domain by German law, though you can do legal moves that are essentially equivalent.)
BSD is also protected by copyright, but it matters less for permissive licenses. It still protects attribution (so you can't claim it yours), but it probably would have worked without it, unlike with Linux that is for a big part defined by the "copyleft" protections offered by its licence.