It makes sense for those of us who probably don't need a full parts gun--why pay $300 for the whole kit when all you need is a new seer? In many cases I'm perfectly willing to pay a bit extra in order to only get the parts I need. Perhaps that's shortsighted on my part, but I don't think the attitude is uncommon at all.
That said, anyone got a 12ga Fox parts frame they want to be rid of?