When you look at 3D movies that did well, such as Avatar, the thing that struck me was that there was a DEPTH to everything. It isn't about objects popping out of the screen, it is about scenes having a feeling that objects are in front of, or behind others. Things that pop out of the screen are more of a gimick to try to grab the attention of a viewer, and it almost always fails.
When you see 3D broadcasts, do you feel like there is that sense of depth? Of course not, because it takes someone with an understanding of what works and what does not to make a new technology thrive. Stereo when it first came out, it wasn't necessary, but it added to what you were watching. Surround sound also adds, but you may notice that it isn't used well all that often(music gets too loud, you can't hear what is being said over the music in some cases, etc). When done well, you feel that surround sound really adds to what you are watching, from crowds of people and people talking behind the viewer, to the sound of shots and explosions that come from all around, not just in front.
Until those who add 3D to broadcasts figure out that you CAN add depth to ANYTHING to enhance it, without objects needing to pop out of the screen, 3D just won't seem like much of an evolution. Again, it will never be seen as NECESSARY, but if it makes the experience of watching a movie, show, or even news broadcast feel more like you are there in the audience, it won't take off.
Things like 4K definitely enhance the experience. If you go into an IMAX(or IMAX experience) theater, you probably notice that the sound and visuals can be spectacular. Rogue One on the IMAX....it really is worth going out to see, but compare a typical movie theater to having a 55 inch or larger 4K TV with surround sound, and you may wonder if it is worth going out to see. 3D....it has potential if done well, but most of the time, you get something that is very low budget.