[dstaley]

You can blame Google for this. They insist on using VP9 for their 4K videos despite the fact that no Apple hardware supports VP9 decoding. I'm hoping this changes once Apple adds support for AV1.

[MikusR]

You can blame Apple and the many h265 licensing pools for that.

[ZeroGravitas]

My MacBook Pro hardware supports VP9 decoding I belive. But I'd need to boot into Linux to use it I think.