Bus dev goes to where the money/market is. the DCI spec says... 2k. so while TI is working on more and better, it is for the Bus world. boardrooms, command and control, etc.
The money in the cinema world is in the area of making the replacement proj for all the cinemas that just drops into the environemnt for the least amount of money and the best specs.
the obsession with 4 K is (to my mind) ridiculous. for HT and even D-cinema, we are not even close to maximizing what we have. Cineramas's little project in fla shows this. If you can get a proj that has been built correctly form the ground up, and is able to take in that HD signal from Sat, BR and higher (broadcast sources) the reality is that it can be so good you would question why anybody could ever ask for more.
Just like with good old nasty ole NTSC. take a first gen transfer from a rank or some other transfer unit, put it on a digital betacam, then tweak a real solid display and it will liekly look far better than many HD displays with off air feeds.
The reality is that we are so far down at the bottom of how good HD CAN look, that talk about 4k is just silly.
It is like cars, butting a bigger engine with more HP is no guarantee of anything other than a higher gas bill. to really improve things, you have to strip that car down and build it back up with attention paid to all the elements.
Or digital cameras. i have an 8MP camera that takes crappier pics than my old 2 MP camera. and if we compared the 10 MP consumer camera to a 6MP PRO camera (which for some odd reason is twice-4 times the price...) the image quality cannot even be compared.
Resolution of the proj has very little to do with the image onscreen.