There would be a limited market for playing 8K videos. None of the movies are going to be on 8K any time soon. I think 8K has commercial use on large screens (stadiums / malls / restaurants / museums etc.) but I do not think there is any real market for 8K in the home front. That said, Zidoo really needs to fix their 4K players first!
The RTD2893 isn't an STB SOC, it's essentially an add on decoder used to upgrade existing display platforms to 8K.