No one saw GotG 3 because of the script, they saw it because it had people they liked from films they liked in it. It was fine and promptly forgotten about. Disney's problem is they don't have any of those left. They're not interested in making any movies with anyone that people actually liked or like.
It will be interesting to see (if this break-glass-in-case-of-emergency scenario of bringing back RDJ, Hemsworth and the others actually happens) if three years from now, which is the earliest they could crap out a movie, anyone still even wants to see the actual likeable capeshit people anymore. I mean assuming production starts in 2025 for a 2026 release, does anyone want to see 59 year old Iron Man? You could make a good story out of old-ass Iron Man, but I wouldn't really trust even good film-makers to do that well, much less these idiots.