They would likely argue that HEVC and H.264 are hardware accelerated on nearly all of their devices whereas VP8 likely isn’t. This would mean compromising on battery life as they’d have to provide a software fallback where needed. I don’t see Apple being very willing to provide a bad user experience and given how hard they were pushing HEVC during their 2017 WWDC keynote the best bet is that they think that’s the better option.
Alternatively they’d have to add VP8 support in their chips and one suspects they would be unwilling to spend silicon on that which could otherwise be used for whatever witchcraft their silicon designers are whipping up.
I’d grant that as a valid technical reason for limited video codec support. Silicon and battery are at a premium.
I always find it disappointing when video from Apple doesn't work in Firefox. There are quite a few JavaScript libraries available these days which support HLS in browsers which don't have built-in HLS support but Apple doesn't make use of them.
> They would likely argue that HEVC and H.264 are hardware accelerated on nearly all of their devices whereas VP8 likely isn’t.
I'm sure a lot of them do, but it's also true that there are a lot of Mac laptops out there which will be upgraded to High Sierra that don't have hardware HEVC acceleration.
Cisco provides a fully licensed encoder, OpenH264, that you can download for free (Firefox uses it). That loophole was removed for H.265, though. I would have rather had only VP8 mandatory to implement in the standard, but at least this situation is better than the reverse.
One obvious technical issue is that, as far as we know, there's no VP8 decoding hardware in any of Apple's products; implementing VP8 decoding in software might be more of a power drain than Apple wanted.
> there's no VP8 decoding hardware in any of Apple's products
But what I found interesting in the WWDC session you linked to was that a lot of Apple products don't have hardware HEVC decode and\or hardware HEVC encode support. Apple has implemented software HEVC decoding and encoding in a lot of places. From that perspective, adding support for VP8 and VP9 wouldn't be much different.
Apple avoid supporting free codecs, because they are part of closed codecs cartel. So they do all they can to delay adoption of free codecs. Note, that they didn't join Alliance for Open Media, while even Microsoft did: http://aomedia.org