Speaking of Endgame's (relatively) unimpressive legs, I wonder why it wasn't considered a disappointment by the same people who called The Last Jedi a box office disappointment. Endgame actually bled out at a noticeably faster rate than TLJ, and, at least according to some people apparently (TLJ's critics, namely), it's the money made after the fourth week in the box office that's the real test of a movie's success.
Because Endgame was still the highest grossing entry in its franchise, and by a very large distance at that, which means that it was seen by pretty much all of its target audience. The Last Jedi, however, grossed considerably less than its predecessor, meaning that many people who saw The Force Awakens didn't bother to see The Last Jedi, or didn't bother rewatching it.
It's not rocket science.