The effort is time-consuming at about six hours for an episode, and the necessary software is both expensive and tricky to work with. Voyager had variable frame rates that make audio sync a pain, as you can see in the sample clip below. It could be a long, long time before you can see Janeway and crew in 4K glory. Still, Reichard hopes to give every episode the AI treatment. Just don't count on CBS sanctioning this, let alone making it officially available.