>> Note: it's unfair to use this to criticize demand curves, which are
>> drawn for a given level of technology.

> The example does assume a given level of technology. Technology is
> specified by a set of techniques. The number of techniques is found
> by multiplying together the number of processes known in each industry.
> Robert Vienneau


But a demand curve only applies to the technology in use - as soon as
you use a different technology you get a new, different demand curve.