[inkyoto]

Yes, they did, but… it was more of a proof of concept and a promise rather than a production quality release. They also had the OS X Server product line at the time (no more), which ZFS would have been the best fit for at the time, and they also released the OS X ZFS port before the advent of the first iPhone.

It is not a given that ZFS would have performed well within the tight hardware constraints of the first ten or so generations of the iPhone – file systems such as APFS, btrfs or bcachefs are better suited for the needs of mobile platforms.

Another conundrum with ZFS is that ZFS disk pools really, really want a RAID setup, which is not a consumer grade thing, and Apple is a consumer company. Even if ZFS did see the light back then, there is no guarantee it would have lived on – I am not sure, anyway.