Thanks to all who have commented thus far. The comments from working economists and sociologists were of particular interest, and I can see that they are going to produce some changes in the essay. I'll plan to discuss these points in more detail in follow-ons to this essay. Finally, frequent comments have led me to conclude that an important element is missing from the definition of agalmics.
Agalmic goods are non-scarce goods, but they are often produced using scarce goods as raw materials.
An important example is the initial programming work which goes into a free software application. At the current state of the human lifespan, programmer time must be regarded as a scarce good. We are now at version 3.0 of the essay. The cooperative spirit of the Internet is not a historical fluke. If human beings allowed their aggressive, suspicious sides to dominate, we'd live in a world in which people took things by force instead of buying them.