@colomar ... copyrights restrict supply and push down demand (down and to the left). It creates an inelestic demand curve.
So, for instance, I don't often refer to nonfree journals because I don't have easy access to them, instead I turn to more open resources that may not be as comprehensive, but still effectively supply my need for knowledge. It is more difficult, but more cost effective.
I will look into this further because I don't know if it is a good enough answer.