I couldn’t imagine watching the originals and then not want to watch the rest. I guess if you watched the originals then decided you didn’t like Star Wars, then maybe, but for everyone else wouldn’t you want to at least see what happens or be able to participate in conversations about Star Wars?
What else are you going to go watch that would be more meaningful than watching the rest of the Star Wars movies? I’m not watching Sonic the Hedgehog for a third time.