It is pretty weird how 4k hardware has far outpaced 4k content. Other than video games, cable/satellite TV providers have very meager 4k content if at all.
Movies are recorded in 8K generally these days, that's literally where resolution is going to bottom out. The return on investment beyond that is so small. Progress will be made but I could see 8K lasting 30 years...
Storage plus speeds.
DVD was a pretty good perfect storm of things coming together that gave it and its associated technologies such a long run. Everything since then has hit and been surpassed or the market has changed right as when it should have hit that point to take off. Streaming becoming mainstream really did a number on this I think even if probably long term is helping to slowly bump up the resolutions. I think Tasty's right in that one of these is going to stick around for costs reasons and it'll just default into being a standard.
Even most “HD” cable offerings are still just 720p/1080i so it’s really no wonder.
To get Directv 4k service, a tech has to come to the house and put a new nose on the sat. dish and you need a special box on the 4k TV. Then they tell you that you need a reliable 22MB/sec internet bandwidth. That makes you wonder if the channel is even over the air. You get 1 full time channel for content and 2 for special events and it can be weeks in between events. At least it's free because it isn't worth paying any extra for.
The HDTV standard that was accepted in the U.S. (and followed by many other countries) doesn't support 1080p. Only 720p and 1080i, as a result the broadcasters don't broadcast over that. The cable networks unless otherwise specified run off the same base hardware because they know the TVs can at least receive that.
There is a higher level standard that changes codecs but it's not required, something like five stations in the U.S. use it and on an alternate feed of their main channel. A bunch of German stations switched to it but I believe that was the only country that did. It also only allows for certain frame rates.
There is at this point a bandwidth limitation on the signal. The codecs used simply cannot handle it on both ends. That's why all the 4K stuff uses satellites and special decoding hardware. IIRC, for over the air TV you can't even switch to a codec like HEVC because all the digital stuff people bought only does MPEG, a lot of them are still MPEG2 even. (IIRC that "updated codec standard" calls for MPEG4, which lots of TVs now support natively due to streaming, downloaded videos, etc.) HEVC, for example, could solve the bandwidth problem but then you need to decode it in your TV fast. And when nobody is broadcasting in it anyway...
I think internet bandwidth's continuing jumps (even if not as we all wish) will simply just phase it out, and since they're all the same companies anyway they'll give you "free local TV" with internet and the FCC will be fine with that. They'll just let the over-the-air standard stay where it is and the networks will just run 720p downcodes.
I don't know if anybody here fucks with OTA digital TV but I've never seen it not be shit quality that drops out constantly unless you have a big ol antenna on the house. It's sometimes worth it though to see a 720p Always Sunny episode letterboxed improperly inside a 480p frame as the video pauses and cuts out every two minutes.