I've followed the televsion industry fairly closely for the last few years. Manufacturers have made significant leaps forward in picture quality while managing to steadily decrease the price tag. The built-in OSes have also steadily improved. I bought a new TV this year and, if it wasn't for AirPlay, I could get rid of my AppleTV and not feel a difference.
I think we'll see more features emerge that allow consumers to leverage their existing video content in easier and easier ways and eventually move content to and stream content from the "cloud." Whether Apple will be a part of that trend when it comes to video remains to be seen.
I'd like to think we'll eventually start see more content in 1080p (and beyond), but that's in the hands of the content producers and providers. The whole 4K-8K thing sounds awesome, but let's not get ahead of ourselves --1080p displays have been available at the consumer level for over 6 years and yet 1080p content is still virtually non-existent in US television broadcasting.
A "retina" TV might be cool but -- if the price tag of the few 4K TVs being pushed to market overseas are any indication -- the costs and margins aren't right for the general market yet. And while one might make the argument that the increased premium for rMBPs has not dissuaded Apple lovers from lining up to purchase one, there is a precedent for high-end, high-cost TVs not selling enough to justify producing/selling them:
In 2008, Pioneer released the Kuro Elite 9G TVs. They are to-date the best TVs ever manufactured in terms of picture quality and (for the most part) picture/signal processing. People who need a true, reference-quality display still use them and swear by them. But the price was way too much for most people to justify purchasing one, TV enthusiasts/videophiles included. About a year later, Pioneer permanently closed their TV manufacturing lines.