Before anyone accuses Paramount of milking the Star Trek series unnecessarily let me remind you that they have done a great job of packaging for each series. There’s a lot of value built in even if they are fairly expensive box sets. You get commentaries galore, and tons of the sorts of special features that send fans scurrying to store shelves. A studio grab would seem out of character. But even I was suspicious about these sets- until I thought about the concept. By arranging the episodes from each series into thematic sets they really do give an interesting overview of phenomena within the Trek multiverse. And these sets make a great affordable alternative.
Not to be a nerd, but Star Trek: First Contact utilized time travel and even Generations had a form of time travel utilizing the Nexus.
-----