Don’t forget that when making ESB he had an actual plan for what would ultimately because RotJ, and the trilogy to follow that… specifically that Leia was not his twin sister (hence the smooching), Yoda’s “there is another” referenced Luke’s actual twin sister somewhere else in the galaxy, and the next trilogy (or at least the first movie in it iirc) was his search for her.

But Lucas got caught up with Indiana Jones and just decided to throw out his plan for SW and wrap it all up.