[paavoova]

Apple is also a member of MPEG LA, and has refused to adopted VP9. With AV1 perhaps they changed their tune and/or had no choice industry wise.

[acdha]

VP9 is a Google project which competed with the MPEG-developed H.265. It’s not surprising that Apple implemented the format they contributed to and then jumped to the next generation format rather than spending time on an older format which never saw significant adoption.