It really boils down to a few gatekeepers (mostly old white guys) giving the screenwriting jobs to the same idiots over and over again. For example, the guys who wrote Morbius have never written a successful film that made money back at the box office but already have 1 new screenplay in production and have been contracted to write several more; meanwhile the screenwriter of Crazy Rich Asians (which not only outgrossed Morbius but nearly grossed as much as Morbius' screenwriters' other films combined) has only been hired for a single film (Raya and the Last Dragon) since.