It always frustrates me to see things like this so undervalued. To me, it seems something like this could have a societal impact on the same order-of-magnitude as the internet, yet the story only has 16 upvotes, and it will probably take over two decades, if not longer, for this manufacturing system to materialize in, for example, my neighborhood. Why is that? I realize there are certain costs to introducing it and it does have its risk (and some problems, as gibsonf1 mentioned), but wouldn't this be a marvelous investment not just financially, but in general for humankind? I suppose the point of my ramble is to raise the question: why is viral marketing so hard to perform in "real life"?