Like any industry based around making as much money as possible, the movie business is full of jargon terms thrown around by various people on the food chain that often mean absolutely nothing. They're just default phrases, much like no matter how you're feeling at the time, if somebody asks how you are the answer is either 'alright' or 'not bad'.
Sometimes these phrases are so transparent in their banality that everybody sees right through it. Take the recent news that Phil Lord and Christopher Miller had left the Han Solo spinoff due to 'creative differences' for example, in the hours that followed it was confirmed what most had suspected; the duo had been fired.
People that follow the inner workings of movies aren't idiots, we all know what this kind of stuff means and so many statements and press releases feature the same combination of tired phrases that it borders on the mind-numbing. So lets cut the crap and see what it all really means.
What it really means: 'We're going to throw everything at the wall and see what sticks'.
It used to be that a script came from one person. They'd write it, somebody would film it and everybody would live happily ever after. However, in the age of over-commercialized studio blockbusters, that is no longer the case.
Multiple scribes working on the same script, or even writing competing ones for the same project, are now commonplace, and that's without even mentioning those brought on during production for on-set rewrites. Having so many fingerprints on what was originally one person's work has the potential to severely dilute the script from first draft to premiere.
Yet in a 'more is more' environment such as Hollywood, they are now assembling teams of writers to map out entire franchises before a single frame has even been shot, which on a base level doesn't seem like a productive idea.
The Transformers writers room involves twelve people working on up to fourteen movies, James Cameron hired four people to assist on his Avatar sequels while Universal's Dark Universe and both the MCU and DCEU feature a myriad of people working on various ideas that must all be passed on to somebody higher up the food chain for approval.
Instead of writing one script around a good idea, there are now several people simultaneously developing multiple scripts while throwing every idea into the mix, safe in the knowledge that it will probably get used eight movies down the line.