I'm a cynic but my view on 4K is pretty simple.
IMHO, 8K is still not realistic for a host of reasons. For streaming, IMHO, it still consumes too much bandwidth even using h265 and it would create issues from an infrastructure perspective if it was widespread. Especially in the US which lags behind many countries in terms of speed and being over-priced. And, the infrastructure just sucks for the most part. I'm still waiting for more widespread 4K streaming and seeing the **** hit the fan when it can't be handled. With respect to 8K on disc while h265 does reduce data size a move to even 4K is so much more resolution. From my perspective 8K will wait until the next generation of media which is much more advanced, etc. New laser technology, etc, or whatever they move on to from laser. That's if we even still are able to buy content on physical media and definitely there will be much newer and more complex protection mechanisms.
The move to 4K is a stop-gap measure. It's expensive enough at it is. 8K is just ridiculous. Enough people will buy into 4K, however, and it's a money-grab. People need to buy a UHD TV to make use, a new UHD standalone player, new UHD discs, etc. Money money money. Lastly, and more importantly, however, a new format with new specs is an excuse to throw in new methods of protection. If they suddenly amended the Blu-Ray spec and added a new profile with AACS 2.0, among other things, and people had to buy a new Blu-Ray player just to watch a new Blu-Ray release there would be too much of a backlash. This is a way to slip the new protections into the mix while also saying, "But look at the resolution! Look at the better compression! It's 10-bit instead of 8-bit! It's mindblowing! Try it. You'll like it!"