What type of fish is good for making profit?

Joseph Schumpeter claimed that the "excess profits," or profits over normal profit, generated by the copyright or patent monopoly will attract competitors that will make technological innovations and thereby end the monopoly. This is a continual process referred to as "Schumpeterian creative destruction", and its applicability to different types of public goods is a source of some controversy. The supporters of the theory point to the case of Microsoft, for example, which has been increasing its prices (or lowering its products' quality), and predict that these practices will make increased market shares for Linux and Apple largely inevitable.