ANH has a soft ending. Everything introduced in ANH is wrapped up before the credits roll. It’s a soft enough ending, though, that ESB and RotJ can reopen it without undermining ANH.

For example, Luke’s arc in ANH is to trust in the spiritual aspect of the world over the material. It’s resolved when he relies on the Force instead of his targeting computer to destroy the Death Star. However, ESB reopens it as he starts to become a Jedi, and his arc is given a hard ending in RotJ when he beats Vader but doesn’t kill him.

But that soft ending is still there in ANH, and you can easily view ANH as the only Star Wars movie.

As another example, Breaking Bad was supposed to end with Season 4. Everything’s wrapped up and every conflict is resolved, and hell it even ends with Walt saying “It’s over. We’re safe. I won.” You could stop at Face Off and have a complete story.

But Heisenberg is still at large, Walt’s still dealing drugs, you can keep the story going from there, and they did continue the story in a fifth season. So it’s only a soft ending.

I don’t know, maybe that’s what’s going on? I’m not Shopping Maul so I can’t tell you for sure but I imagine that’s what’s going on.