There is another myth, equal and opposite to the factory-model delusion, which often confuses peoples' thinking about the economics of open-source software. It is that ``information wants to be free''. This usually unpacks to a claim that the zero marginal cost of reproducing digital information implies that its clearing price ought to be zero.
The most general form of this myth is readily exploded by considering the value of information that constitutes a claim on a rivalrous good -- a treasure map, say, or a Swiss bank account number, or a claim on services such as a computer account password. Even though the claiming information can be duplicated at zero cost, the item being claimed cannot be. Hence, the non-zero marginal cost for the item can be inherited by the claiming information.
We mention this myth mainly to assert that it is unrelated to the economic-utility arguments for open source; as we'll see later, those would generally hold up well even under the assumption that software actually does have the (nonzero) value structure of a manufactured good. We therefore have no need to tackle the question of whether software `should' be free or not.