Also: if you’re doing 2160p 10bit HDR, there’s no chance those Rokus are going to play them anyway.
Disclaimer: not involved with the scene at all, so this is mostly educated speculation.
But I imagine those in the scene are more interested in being the first with a passable 1080p Blu-Ray rip than they are in cramming as many high quality movies on their iPad as possible before a long flight.
If they could reduce bitrate while getting the same quality, they would. If they could get even better quality while having the same bitrate, they would do it too. The problem is at their quality level requirement x264 is still king. And as of late 2018 that still seems to be the case. ( Tuning Encoder is a god damn insane job )
I have some 10bit 2160p ATMOS remux movies that are huge 50GB MKV files and I stream them over my gigabit LAN to a no-name $80 Android box I got off some obscure Chinese marketplace and it plays them back perfectly with full HDR and my amp gets the atmos signal too.
If your device has hardware based x264/x265 chips it can decode them with very little processing power.
Being furstcwith the release is. And then you don’t want to spend 10x-50x more time on your encode.
The incentives here are nothing like YouTube.
x265 is nowhere near that much slower unless you are using a very high preset. Even preset #9 ("slow") is only about 2-3x slower than x264, in my experience.