People like Marvel movies, but I think Quantumania proved that even with the MCU, average movie goers really aren't that interested in overall story arc. They made a huge deal all over the place about how Quantumania was setting up the big storyline for the next phase or two of movies, and introducing Kang, who's going to be the next Thanos, but with all of that, it still more or less ended up being a flop. If non-hardcore fans were really that investing in it as a cinematic universe, then it would have been another $1,000,000,000 movie.
All that means is that people are interested in what Henry Cavill is doing, that doesn't automatically mean people care which movies are part of which shared universe.
Yes, people do pay closer attention to that kind of stuff these days, but again just because they're interesting who's doing what, that still doesn't mean that the average person cares if a DC movie is set in the DCEU or the DCU. All they care about is that there's a new Superman, Batman, or Wonder Woman movie coming out.
I'm not so sure about there, I'm pretty sure there are still a lot of non-sci fi fans out there who would say exactly that if you asked them a question about Star Wars.
I think the problem here is that people who are part of a group and have special knowledge unique to that group, tend to assume that everybody has that knowledge too, when in fact most people outside of that group don't. I'm an big animal person, and I'm constantly shocked how much stuff I've known forever and I assumed everybody knew, that most animal people actually don't know.