Maybe I'm being nostalgic but Mickey used to be a big movie star and now he's relegated to mostly direct-to-dvd. He was still immensely popular through the 1980s with rereleases of Fantasia in theaters, Mickey's Christmas Carol, etc. Now it seems unimaginable that he'd star in a big budget Disney film. It seems reasonable to me that they are preferring IP that was created post-1976 for a reason.