[quikee]

Apple probably held off adoption so that HEVC patent license situation improves a bit (at least most companies with patents join in some pool or start to offer licenses).

If AV1 would be released sooner it wouldn't be even as good as HEVC, which would be bad. VP9 is already that free-but-not-as-good-as-HEVC codec. Also they would need to release AV2 in 1 or 2 years (as the better-than-HEVC codec), which is just too soon after AV1 and would put a big question on why AV1 was released at all...