The movie looked like schlock to me, so it doesn't surprise me that most of the world wasn't inspired to go see it. The Weinsteins, as well as Tarantino and Rodriguez have been taken down a notch or two, and that is not a bad thing. They've been trading on their names and not their skills for too long.
Splitting the movies up is a last-ditch effort to salvage what they can, but it likely will fail. The whole point was to make an exploitational double-feature, so the in-joke that drove the entire project will be lost.