The problem with those standalone IP's is that they don't get enough love, and it makes it harder to make more of them. Look at Jupiter Rising, or anything else in that vein. It was a completely original idea, but no one went and saw it. It's a death spiral that we can't seem to escape at the moment. Maybe in a few years, people will start to trend back to self-contained stories, but it seems for now we're stuck with universes, many that shouldn't be. At least the superhero ones were designed to be inter-operable from the beginning. There are some really strange ones out there now, like the monster one that was Universal was supposed to be putting together.