But... I don't think that detracts from my main point, which was to give an example of a technology that was "simply too cheap to be developed" that was, in fa

But... I don't think that detracts from my main point, which was to give an example of a technology that was "simply too cheap to be developed" that was, in fact developed. Sure, for various reasons it ended up not costing pennies, but my point is just that the underlying concept is extremely simple and if you ignore all the things that makes good engineering expensive, and all the things that make medical devices expensive, potentially quite cheap.