> Now, this analogy does not work at all, because going by the painting in the museum in no way implies you would want it at home.

You are talking from a buyer's perspective (the museum visitor) whereas he is talking from the seller's perspective (the museum / artist). The seller hopes that by allowing you free or cheap access to the art, you may be tempted to buy a copy of it or some memento of it (which is one of the ways museums / artists make money).