I can't agree with those trying to parallel the 3D experiment with UHD's situation. Too many basic differences.
I see basic similarities ... especially with ESPN's involvement. When HD came out ESPN started a HD channel - not a 24 hour simulcast but as much HD content as they could get. ESPN HD (and eventually ESPN2 HD) replayed HD content - one could expect to see sports in HD 24/7. Eventually the amount of HD content grew and both channels became simulcast with their SD channels.
ESPN 3D followed the same path. They released a channel similar to their initial HD channel ... all 3D all the time but obviously not a 24/7 simulcast (since not everything on ESPN was available in 3D). 3D eventually faded and so did ESPN 3D ... but the start was the same as the HD channels.
ESPN 4K/UHD will likely follow the same path as HD and 3D ... a showcase sports channel that plays 4K/UHD programming around the clock. Eventually when enough content is available in 4K/UHD it will become a simulcast with the HD channel - and a second ESPN 4K/UHD will be born. The path seems fairly clear.
As far as other channels ... the introduction of HD brought special HD only programming channels. Some that have survived past the "look at this, it is in HD" novelty phase and joined traditional channels that upgraded their programming to HD. The early days of HD had a handful of linear channels and PPV. The introduction of 3D also brought special 3D only channels ... including "look at this, it is in 3D" novelty channels and PPV. Unfortunately 3D faded before traditional channels such as HBO joined in.
With 4K/UHD on the horizon I expect the same type of "look at this, it is in 4K/UHD" novelty channels that we saw with 3D and HD. I expect to see ESPN 4K/UHD. We already see VOD and PPV. When traditional channels step up and introduce 4K/UHD channels (such as a HBO 4K/UHD channel) it will be a good thing for the 4K/UHD marketplace.
I believe DirecTV intends to support 4K/UHD and see where it goes ... just like the supported 3D (and still do). If there is content to carry they will offer it. DirecTV made the commitment to upgrade their receivers to handle 3D ... they are making a similar commitment to handle 4K/UHD.
The work DirecTV put in to 3D is a good thing ... it shows that they are willing to make a commitment without a guarantee of success. That they are willing to be a market leader even if what they offer eventually fades. If they were not willing to take the risk with 3D I wouldn't be so confident that they would push ahead with 4K/UHD.
The future of 4K/UHD has yet to be written ... but it seems safe to say that DirecTV is positioning itself to be a part of that future and give 4K/UHD the best chance of survival beyond the "novelty" phase. That is a good thing.