They absolutely can ship it. They choose not to. There is a big difference.
It's what happens when ideology is allowed to trump technology, and it is sad.
The fact that various distros ship not-open video card drivers shows that for some things, there's a willingness to compromise. This is far "worse" than shipping an open source module, or open source code that is compiled into a module on install, either of which could be done for ZFS.
The non-free drivers are allowed to be redistributed by the copyright holders. The reason to not distribute them would be ideological.
Linux and ZFS's licenses are incompatible, which would make it illegal to distribute them together. Both ZFS and Linux copyright owners could choose to sue any entity that would distribute Linux with ZFS support.
You take quite a logical leap from "licenses are incompatible" to "illegal to distribute them together." I'd love to know what led you to that conclusion.
As I said to the other poster, you're just spreading FUD.
If the licenses are incompatible, then you cannot ship them together. Calling that FUD is a bit rich! Try going through the process at Fedora. The legal team will stop you.
Licenses allow you to distribute things despite copyright. Usually distributing software without a license is illegal, though there are exceptions in some countries for music and movies.
You can obviously nitpick about that he uses "illegal". However, the discussion was about why ZFS is not distributed. That is what the answer was about, incompatible licenses making it (somewhat) impossible for distributions to carry it.
Now various distributions do have e.g. "nonfree" repositories, but incompatible licenses are a big problem. Responding to such concerns with "just spreading FUD" seems to (hopefully) indicate you're not involved with any distribution.
Dude, that's literally what "licenses are incompatible" means.
The GPL gives you a license to distribute IF AND ONLY IF all the linked binaries have AT LEAST the same permissive rights as the GPL mandates. The CDDL gives rights SIMILAR to GPL, but in a way that is incompatible, i.e. which does not let you distribute CDDL code with all the permissions the GPL mandates. As such, you void the license to distribute the GPL code, as you're unable to comply with the GPL license (i.e. the bit that all linked binaries have at least the GPL enforced liberties).
The GPL's license to distribute is dependent on you distributing binaries with the appropriate permissions and the CDDL won't let you.
Please provide reasoning why you think it's "illegal." Otherwise, you're just spreading FUD, which is the whole reason for people believing a Linux distribution can't ship ZFS on Linux in the first place.
Please provide reasoning how it is ok to distribute it. CDDL is incompatible with GPL. Distributing that would allow your distribution to be sued for copyright violation.
Apart from that, e.g. each time you update your kernel you would have to recompile the modules for that specific kernel. ZFS is also an FS and i wouldn’t want to play jeopardy every time i do an update.
You depend on people outside your distribution to keep up, otherwise it might break when you upgrade your kernel. It's also basically in a perpetual beta.