The signage industry is, of course, about pro displays and not TVs, even if the TVs are pretty awesome. But all those 4K TVs and the normalization of 4K means more content being produced at that resolution and a consumer expectation of how they see motion media.
Does that mean someday soon everything needs to be 4K? No, not at all. There are many, many, many situations where even 720P is going to be fine, given sightlines and the type of content. But there are going to be more cases in which 4K not only makes sense, but from the perspective of the audience, would be somewhat expected.
There’s still, however, not a lot of material being produced in the format, and the steady push to drive cost out of hardware media players means there are not a lot of boxes out there that can “do” 4K UHD well … at least not at the tiny price points a lot of the market seems to want.