The Lucas Effect
Although prequels and sequels frequently bomb, I use "The Lucas Effect" to characterize filmmakers who continue churning out increasingly poor films that are still financially successful. Also, almost certainly there are more cases of The Lucas Effect than just these; I'm sure I simply haven't seen them yet.
For me it started with George Lucas: the original Star Wars trilogy was rightfully regarded as a groundbreaking series; however, its success created a feedback loop in which Lucas' ego became so bloated that he felt free to throw anything he cared to at the screen, with no regard for what makes good entertainment. Meanwhile, his salivating fans dutifully bought innumerable tickets (there's a reason it's called "disposable income"), further encouraging their idol to make more crap. Thus, despite the fact that his prequels were critically utter garbage, they earned Lucas billions. No accounting for taste.
In his commentary for his three prequels, Lucas repeatedly enumerates a number of significant rules of filmmaking in order to justify his penchant for vomiting on the screen. He fails to get that following a few rules doesn't mean the finished film is worthwhile. It's as though he took Filmmaking 101 and followed a bullet list of specific items he jotted down without first checking to see if his script, cast and direction were worth the financial investment. So what if he followed this convention or that rule? A crappy script, actors with no chemistry, lifeless direction, and a consistent disregard for good storytelling can't be saved with a bigger effects budget. (George, check with your friend Steven Spielberg, because he figured it out a long time ago. Also, I know you hate him for making a better Star Wars than Star Wars, but J.J. Abrams has you beat by a billion lightyears.)
Ridley Scott is another notable Hollywood figure afflicted by the Lucas Effect: his Alien prequels were a waste of celluloid (or disc space, as is the case with digital film), and yet they were profitable (no accounting for audience taste once again). And now it would appear that J.K. Rowling is the latest victim, as her Fantastic Beasts films—prequels of sorts to Harry Potter—are proving to be critical bombs. Curiously, her symptoms parallel Lucas' quite closely in that they obsess over building detailed political backstories for their respective franchises: Lucas has gone overboard about the minutiae involving the "Old Republic" transmuting into the "Empire," one stupid freaking trade embargo at a time; meanwhile, Rowling is attempting to conjure intrigue with the inner power struggles of the Wizarding World, including a full-bore election—decided by, of all things, a mystical faun. Yawn.
Other symptoms of The Lucas Effect are that their films become ever longer, and they also feature ever-increasing amounts of music. Lucas' prequels have almost no music-free scenes (which he explains away with some nonsense justification), while James Newton Howard's soundtrack for Rowling's Secrets of Dumbdore is nearly two hours long. It's as if the filmmakers are attempting to compensate for the lack of worthwhile story, although I'm sure they believe more music gives their films more (apparent) importance, but who knows? And who cares, really?
Incidentally, I ought to include Peter (Lord of the Rings) Jackson and James (Avatar) Cameron in this bunch as well, if only by virtue of increasing film length—Cameron's Way of the Water is three hours long. Not to mention that Cameron went off on critics' reaction to the film's length even before the film was released. What a pompous dick. Please, give me a (bathroom) break...