When Disney released The Force Awakens to reboot the Star Wars franchise under their awful wing, it was perceived with mixed reactions, it was inevitable. However, fans of the franchise saw it as a good entry, taking on little risks as it established the world and characters for what would be a trilogy.
The unknown problem, however, was that Disney itself had no clue whatsoever of what to do with the trilogy. With The Force Awakens sitting under the control of J.J. Abrams, and its sequel given to a random guy, Rian Johnson, The Last Jedi was given no indication of what direction it would be going in; although, presumably under the expectation of fans, it would be a second entry that further develops the characters we didn't really know that much of in the first film.
Rian Johnson completely ignored the former events within The Force Awakens, and The Last Jedi went in its own direction, ignoring any chance of true character development, sticking to typical nostalgia and general events that just didn't really fit or make sense. A trilogy was handed to two different people, with neither of them having any idea of where the trilogy would go or even end.
The Last Jedi introduced new characters to the film, characters that themselves were given no time to develop and be understood; in fact, even their motives seemed off. One leader had a plan throughout the entire film, acting tough on the characters throughout it, only to tell them in the end that everything is fine and what the plan was, which simply made no sense.
With the Han Solo film bombing at the box office, it's of no surprise that fatigue for the Star Wars franchise may be setting in. While fans care about the original cast and characters, they are willing to give new ones a chance, but that chance has not yet been given. The Han Solo film didn't take itself that seriously, once again throwing comedy in front of the characters and strangling potential growth. The result is simply mediocre experiences that aren't worth the initial cost for viewers.