I just don't see any explanation other than greed. I would buy the OS for, let's say, U$ 100. What is already expensive for a limited os, but... Anyway, I would do that because of all my past with this marvelous machine IF for example, I could run it on a large selection of PPC machines: PowerMacs, Ibooks, Powerbooks, Mac mini and etc... Drivers could be downloaded freely from the company website...
ANYWAY, this opinion is maybe shared by 90% of the Amiga community that sometimes even having the money, refuses to buy such a mediocre and obscure hardware for this exorbitant price...