I would argue that Star Wars was rebooted, somewhere around the middle of Return of the Jedi. At that point the story shifted tremendously and went from being Luke's story to being Anakin's story. The prequels are in many ways a reboot in the way that TNG was a kind of reboot. Same universe, same essential thematics and tone, reworked hero's journey.
And Star Wars probably will be retold again later. Probably not until Lucas' kids own the rights, but the idea that the Lucas estate won't, in the model of the Edgar Rice Burroughs estate, license out the tale for new versions, or continuations, is pretty far-fetched.
See, it has to do with controlling the copyright. Artistic works enter the public domain some number of years after the initial copyright - for printed works this has to do with publication date, for visual artworks it has to do with the date of the artist's death - and it varies from country to country. For instance there was a flap over Project Gutenberg putting the text of Gone With the Wind up - Margaret Mitchell's estate claimed they still held the copyright, which releases to the public domain 95 years after publication - but only in the US. In Australia and a few other countries, it releases 50 years after publication - so the internet is complicating things mightily.
Filmed works, especially filmed works owned by corporations, which never die the way individual artists do, are another case entirely. Disney has been fighting it out in the courts because Mickey Mouse's copyright was supposed to hit the public domain a few years ago, but Disney is fighting it tooth and nail.
Regardless, Star Wars is likely to hit the public domain at some point, and someone will absolutely use the universe and/ or characters in a new story.
Star Trek, being owned by Paramount, may never hit the public domain. But they've shown the will to reboot it as they feel necessary to make a continued successful commercial property.
But ultimately - any story of any staying power eventually gets retold. I mean, people do it by the truckloads already with fan fiction. You basically can't stop people from reworking popular stories - though you can keep them from being able to make money doing it.