The Economic Value of 3D Printing?

On a visit to the London Science Museum, my oldest grandson explained to me how 3D printing works.  I expressed doubt about its economic value, but he pointed out this sign.  “Aha,” I said, “here is a clear-cut case of a technological change that should reduce long-run average cost (by saving on materials).”

And despite the last sentence of the picture, this saving will eventually be passed onto consumers in the form of lower ticket prices, but probably not fully in the oligopolistic aircraft manufacturing industry.

(HT: JCH)