[noggin]

Looking once more on the datasheet. It seems it is not AV1 capable from hw pov. That means, even if the SW matures a lot - you probably have to replace it next year christmas. Really not sure what they thought ... perhaps they frequenctly fix their android implementation which I highly expect from google, then we have some fun with it.

For most platforms I expect AV1 will be supported alongside, rather than replace, h.265 for UHD HDR content - as so many existing hardware players (Smart TVs, Fire TVs, Apple TV 4K, Roku etc.) used for Netflix, Prime, Disney+ etc. 'in the field' won't support AV1 yet, and it won't be an issue for UHD BD Rips, BD Rips or DVD Rips unless they are re-encoded in AV1 I guess.

Looks like Android Smartphones already have limited Android Netflix App - AV1 support via the open source dav1d decoder.
Netflix is using AV1 to save on Mobile streaming data usage., see the netflixtechblog (click)

Yes - but Netflix is still available to subscribers who don't have AV1 compatible handsets isn't it? My point is that support for AV1 may not be 'must have' and instead be 'nice to have'. It will potentially improve the quality for people on low bitrate broadband and LTE/3G connections I guess too - but Netflix et al aren't going to switch off streams for non-AV1 clients any time soon are they?  I guess the software implementation for 720p and 1080p streams is within the processing power of some portable devices - but it will be interesting to see if hardware decode of h.265 vs software decode of AV1 has a battery life impact ? (Historically CPU decode is not favoured over hardware decode on battery powered devices for this reason - and that's why hardware decode is still a thing?)

I know Kodi v19 Matrix (click), CoreELEC, possibly LibreELEC too has libdav1d (SW decode) support.

Platforms like YouTube that Google own may start restricting their very high-end streams like 8K (or 4K?) to AV1 I guess - but do you see it being a major limitation?

I don't see it being an issue either for 4K video playback. If 8K ever becomes popular then AV1 might gain some decent traction.
Google is not about to abandon their free to use VP9 codec.

The compelling reasons for AV1 adoption are lower bitrates (i.e. cheaper for content owners to stream) or higher quality at a given bitrate (i.e. make your platform more compelling for subscribers) - and possibly also lower/zero royalties to use it.