All numbers rounded to the nearest million:I will point out that the episodic follow-up grossed over 1 billion, which is nothing to sneeze at.
The Force Awakens Box Office Gross: $2,065 million
The Last Jedi Box Office Gross: $1,332 million
The Rise of Skywalker Box Office Gross: $1,073 million
I think that's enough said.
The Last Jedi was garbage and brought the whole sequel trilogy down with it by trashing everything that was set up in The Force Awakens and leaving a huge mess for The Rise of Skywalker to follow up.
The main culprits though are the bigwigs at Disney/Lucasfilm, who decided to start making the sequel trilogy without creating a story outline for the whole thing first, and giving the directors too much freedom to do whatever they wanted. The original trilogy is a tight, self-contained story. Even the prequel trilogy has a halfway decent story underneath all the poor execution. The sequel trilogy makes the prequel trilogy look good.
That said, it hasn't been all terrible. Rogue One was a decent movie and some of the TV shows that brought in creators who actually care about Star Wars and its background lore were good as well. I'm skeptical about season three of The Mandalorian though. They made the utterly stupid decision of undoing the fantastic ending of season two in those two episodes of the execrable "Book of Boba Fett."