Of course, Oracle also controls Btrfs, right?

Meanwhile, it seems that the NetApp patents in question are at least starting to expire. Their earliest asserted patent appears to have expired last year. (But the rules on expiration are non-trivial, so if it's not dead now, it will die very soon.) The later NetApp patents are still in force.

If Apple wanted to revisit the issue, they could almost certainly afford to mount a vigorous defense against patent infringement, especially if they deliberately engineered a filesystem with the specific purpose of working around the various patent requirements. What's sad, however, is that I don't think Apple really gives a shit about instant snapshots and other such things. Those are things you really want on file servers, which Apple once sold but doesn't sell any more.