I can maybe see sporting event broadcasts using 120Hz since people are already acclimated to watching 720p60 HDTV, but will consumers actually say "I want 120Hz video" or will they instead say "I just want to watch my team/TV show?" I have trouble believing that all but a few technology enthusiasts will consistently notice the difference and demand 120Hz video. 4K broadcasts (and 3D before it) suffer a similar issue. HDTV succeeded only because it was such a dramatic and perceptible difference from 480i. Perhaps convincing people to upgrade from 1080i30/720p60 broadcasts to 4K/120 broadcasts might be possible, but if 4K60 catches on then 4K120 will never become popular because it is an incremental upgrade.
Convincing filmmakers to use HFR is, in my opinion impossible. In modern filmmaking you could call 24Hz video a cinematographic effect because there's no good reason to use it otherwise. The only reason that 24 Hz is "cinematic" is because it's what cinemas have been using for people's entire lifetimes, and therefore people associate any 24 Hz video with cinema. I have seen the Hobbit films in 4K 3D HFR at the local theater and thought they looked spectacular, but in contrast all the friends with whom I went to see it thought it looked "fake" or "too much like a TV show" at 48Hz. I just don't see how that battle can be overcome to convince people to give up the effect; I equate it to the same as eliminating the huge fireballs from film explosions (because explosives don't actually generate conflagrations), but it's standard practice and continues to be used because that's what people want to look at and that's what filmmakers have been using all their lives.
HDR images are a slightly different problem because you need a dark room to actually make use of the technology. If you look at the HDR images in a bright room, maybe with natural sunlight or at least with the light on, you can't see the details in the lower range and the lower range just becomes black. Just like with 3D content, you need specific viewing circumstances to make the most of it, and from what I've experienced. most people aren't going to bother with creating ideal viewing conditions or even worry about picture quality or else we wouldn't see masses of people buying $150 LCD TVs with 200:1 contrast ratios.
In the end, the success of such a technology isn't technical at all. The success all comes down to whether consumers demand the content, and while I support the idea, I just don't see the average consumer caring enough.
We've been stuck at 50/60Hz for far too long.
