not sure why 4K content hasn't taken off like HD, probably because most folks think HD is plenty good enough
Again, I work in close proximity to this industry, so there are a lot of reasons:
1) Lack of content - until there is enough of a pull for broadcasters to not only record, but also do all their post-processing and everything else for UHD, the content is truly limited.
2) Lack of equipment - cable/satellite providers like to keep equipment in the field as LONG as humanly possible. They paid for it, they make money renting it to you, and if they have to replace it with new-fangled models it cuts into their bottom line. Until they have enough content to justify charging you more for cable, they're not going to have a lot of 4K. Right now most of the 4K content you can get is video on demand through them, and only if you have their newest boxes.
3) Lack of bandwidth. Cable and satellite are very bandwidth-limited, because they are true broadcast. And remember, when they
broadcast a channel, they have to broadcast it to the lowest common denominator. The signal that comes in your coax from the cable company or to your satellite dish contains EVERY show on EVERY channel, in EVERY encoding scheme they support. Remember, they want to keep old equipment in the field forever. So even though UHD takes advantage of HEVC [high efficiency video encoding], any older boxes don't have HEVC decode capability. The new-ish boxes have AVC / MPEG-4. Older boxes are MPEG-2. That means if they want to provide a program in 4K, it requires additive bandwidth to ALL the stuff they're currently providing. So if they're providing "CBS", they need to provide CBS in UHD with HEVC, in HD with AVC, and in SD with MPEG-2 encoding. Right now it's just the latter two. Otherwise to send you a bunch of 4K channels means they have to go replace your Grandma's set top box that she's been paying $7/month over the last decade if they want to get rid of all their old MPEG-2 signals. And everyone else's grandma too.
3a) This is actually why the streaming services are beating cable to 4K. Netflix and Amazon already have it. Why? Because they're IP services as opposed to broadcast services. Their bandwidth is point-to-point, not broadcast. They send you ONLY the show you want to watch, in real-time. This was also the way that AT&T UVerse and Verizon FIOS work, but those services didn't take off all that well. It's also why you get 4K content over VOD rather than broadcast, since VOD is an IP service.
4) Lack of consumer demand. A
report a month ago said that ~90% of the TVs in the US are not 4K/UHD. Now, while it's true that this is a bit of a weaker point, as a lot of the main living room TVs are being replaced by 4K, it's still not overwhelming. Why put all that content out there when most homes can't even watch it in 4K?
I do think it might take off a little more quickly this time. I think the streaming services will force the cable/satellite guys to push a little harder to avoid losing more to cord cutters, and we should start to see OTA rollout in 2019. When you can get your OTA channels and your streaming services in UHD but the cable/satellite guys don't offer it, they're going to have to catch up.
