I guess it's used only as an example, but we are really far away from being able to 3d print shoes. Or toothbrushes for that matter. Shower-curtain rings and toothbrush handles, yes. I suspect the author of this article has not spent a lot of time looking at the technical side of 3d printing: it's not some kind of magic replicator that can produce arbitrarily complex compound items out of arbitrary materials.