Take Dark Phoenix, the "final" movie in Fox's X-Men series. Before it lost Fox/Disney hundreds of millions of dollars, and even before Disney bought Fox, plenty of people figured that this would likely be it for the franchise. They even had to sign up most of the main cast for one-movie deals because their contracts had run out. But despite this, it still finished with a hilariously optimistic hint that the Phoenix was around and ready for a sequel. Even funnier, this hint occurs while Xavier has openly retired and nonchalantly playing chess with Magneto. That's about as much of a metaphor for the dying franchise as you need.
Even though the last ten years have been the subject of copious "This is when people will finally get tired of superhero movies" thinkpieces, they still make more money than some entire countries. And because of this, rather than truly give these characters closure, they have to wrap it up with "And then the heroes overcame their personal demons and brought peace to the land! Maybe. We'll see."