HT Toby Bates, Ph.D. student extraordinaire. The slinky doesn't fall until the top transmits information to the bottom. It is as if it were levitating. It's highly mysterious if space is a container that objects fall through. But it's not mysterious at all if space, as we know from Einstein in another way, is an emergent property of things.
It's terribly hard to explain motion unless you think objects are intrinsically displaced from themselves. If you think they fall through something, you end up with Zeno issues.