It's just the facts. Look back at the late 1960's and you can find part of the answer. The old Hollywood guard was under attack, and it was just the beginning. There was Coppola, Altman, Hopper, Cassavetes, Allen and others who wanted nothing to do with the old ways of the Hollywood machine. They wanted to make films their own way.
Studios are willing to spend money, but only if they think they can get it back, and then some.
Clearly MGM, then Warner Bros., had little faith that anyone, let alone Kubrick, could make money for them from such a project. Kubrick himself was also to blame. He demanded that the lead be played by an unknown. But most likely he didn't want the story to be overshadowed by a star. He really wanted Jack Nicholson to play Napoleon, but the studios wouldn't hear of it.