That's pretty much it, except that nobody big has actually tried doing that (distributing an install CD which specifically builds ZFS as part of the standard in

That's pretty much it, except that nobody big has actually tried doing that (distributing an install CD which specifically builds ZFS as part of the standard install process), therefore it's not been in courts, therefore it's not proven that it's legally safe to do so, therefore anyone larger than a small business is unlikely to build on top of it.