We'll see.
Everyone will go see this movie, it's a Star Wars movie after all. The question is, how many will see it again? I've seen every Star Wars movie before this turd more than once in the cinema (thanks to the re-releases of the original trilogy.) I even saw the prequel trilogy movies several times. I've bought them all, then bought them again on blu-ray.
I have no interest in seeing this movie again.
Remember how long The Force Awakens stayed in cinemas? It was there for months and months, because people were going to see it again and again. I don't think this episode will enjoy the same longevity. People will buy a ticket to a Rick-roll if it has the Star Wars name on it... once.
That's how you kill a franchise. Look at Mass Effect 3, for example. The ending really "subverted expectations" (which is my new euphemism for "sucked") and despite excellent reviews and strong pre-order and launch sales, the fans of the Mass Effect series were not pleased. Mass Effect Andromeda tanked. EA found out they couldn't get away with that crap a second time. If Andromeda had been good, I would have bought it after I saw some positive fan reaction (I'm done paying attention to professional reviewers for movies or games.) Instead, based on what I read, I decided that if the complete game + DLC goes for less that $20 I might pick it up, if I have nothing else to play. This from a guy who was in the habit of pre-ordering the collector's edition of every BioWare game.
Disney has been talking about the Rotten Tomatoes score being the result of trolling, and pointing the CinemaScore as being a more accurate read of viewer reaction. I hope that someone at Disney is smarter than that. I hope they don't pull an EA and double down, producing another entry that... subverts expectations. Hopefully Disney and JJ are paying attention, and will put effort into wrapping the trilogy up with an episode that exceeds expectations.
We'll just have to wait and see.