The point of trade is to allow each party to get what they want at less cost than they would be able to get independently. If one party wants to sell, but the other party doesn't want to buy, then trade does not happen. This is not bad thing. In fact, per Micah, it's even idyllic: "every man sitting under his vine and under his fig tree." That is, every man having his own food supply so that he is not dependent on someone else.
Defining supply to require a corresponding demand makes this explicit. An entrepreneur can't just start producing stuff that nobody wants and then complain that there is no demand for his supply. He's not entitled to force a trade.
Examples make this clear. The auto industry has the capacity to produce many more cars than they do. But they will not be heard to complain that people should be forced to buy more cars so that they can produce more. Likewise movie theaters with empty seats are not allowed to force people to buy tickets.
By the way, there are industries that partner with government in order to be able to force trade. The money industry is the biggest one. See G. Edward Griffin's presentation of The Creature from Jekyll Island (http://video.google.com/videoplay?docid=6507136891691870450).
Defining supply to require a corresponding demand makes this explicit. An entrepreneur can't just start producing stuff that nobody wants and then complain that there is no demand for his supply. He's not entitled to force a trade.
Examples make this clear. The auto industry has the capacity to produce many more cars than they do. But they will not be heard to complain that people should be forced to buy more cars so that they can produce more. Likewise movie theaters with empty seats are not allowed to force people to buy tickets.
By the way, there are industries that partner with government in order to be able to force trade. The money industry is the biggest one. See G. Edward Griffin's presentation of The Creature from Jekyll Island (http://video.google.com/videoplay?docid=6507136891691870450).