We had a long journey to get where we are now, with HDTV and large, flat screens, and surround sound in the "home theater". It was a worthwhile journey, because now we can watch the entire back catalog of movies, going back many decades, pretty close to the way they were meant to be seen. That was the destination, and we've finally arrived, and there's really nowhere else to go from here. The technology is a solved problem. 3D and 4K are answers in search of a problem.
From now on, it should all be about the content. Movie making, as an art, was largely perfected by the 1970s -- and yet, somehow a lot of bad movies (to say nothing of TV shows) still get produced. Putting them out in 3D or 4K won't make them good.