The DC Universe movies are the length they are for budget reasons. Making them longer would cost more, and then they wouldn't turn enough profit to keep making them. If they were ever to do a long-form story, it would have to be structured and budgeted as two movies.
I don't see Crisis on Infinite Earths working as a standalone movie. It's too dependent on a wealth of prior comics continuity, and has too many little stories clumped together, many of which are just glimpses of stories that are told more fully in the characters' own titles. I read it recently myself, and even knowing as much as I do about DC characters and continuity, there was a lot that was hard to follow or unsatisfyingly incomplete. And it wasn't really one story so much as several consecutive stories. It's too much an entity of the serialized, interconnected storytelling structure of comics. It just wouldn't work as a movie. Maybe you could take one particular thread from it and make a movie out of it, but something anywhere near complete would just be too cluttered and unfocused to work.
I don't see Crisis on Infinite Earths working as a standalone movie. It's too dependent on a wealth of prior comics continuity, and has too many little stories clumped together, many of which are just glimpses of stories that are told more fully in the characters' own titles. I read it recently myself, and even knowing as much as I do about DC characters and continuity, there was a lot that was hard to follow or unsatisfyingly incomplete. And it wasn't really one story so much as several consecutive stories. It's too much an entity of the serialized, interconnected storytelling structure of comics. It just wouldn't work as a movie. Maybe you could take one particular thread from it and make a movie out of it, but something anywhere near complete would just be too cluttered and unfocused to work.
