For some material reason, the big chunk of franchises - especially Star Wars, and the one I meatride the most Halo - took a downward spiral in quality starting in the 2010s?
My personal theory is because of the undemocratic nature of big media studios allowing and even encouraging substandard writers to steer them in dangerous directions causing hundreds of hours of talent being wasted.
It’s because a “safe” and focus tested film/game etc is less risky than doing someone new or original. So as budgets increase, the suits at the top want to make less and less risky projects, which means only allowing things audiences have seen a thousand times before. It also doesn’t help that media is becoming more and more monopolised, which means there’s not small studios that can actively challenge the larger ones, forcing them to remain somewhat creative and competitive.