Yeah, that's the excuse, but seems like every batch is small-run, limited release, exclusive collectors edition, but somehow more and more stock keeps coming back over time. They're expensive even by Warhammer standards, but at least Warhammer figures have detailed work from an artist on them.
> I would bet the case is probably cheaper.
You're right on that, actually.
I can all but guarantee you that fancy custom keycaps are rarely going to be done in runs big enough to have the economies of scale drive down the cost of tooling. Particularly with double shots and the like, those molds are extremely expensive. I don’t doubt that the products are luxury priced, but I think you might be surprised by what the costs are here.
From what I've seen, a typical new keycap set is 90% existing tooling in a new colour-wave, and 1-10 completely new legends, usually that define the theme (there are seemingly 300 sets with Hiragana sublegends, but this one will have a Windows-logo key replaced with the Strawhat Pirate flag!)
I suspect there are efficencies to be found by pooling overlapping orders and reducing nonstandard kitting. Saying "everyone gets the 3/£ keycap" adds 20 cents per order, rather than making a few UK users buy a low-economies-of-scale kit at $25.
I've been fond of Maxkey's caps-- they seem to have achieved that accidentally. They seem to sell one basic cover-all set in different colours, and as a result they have pretty good supply and modest prices (their sets sell for about USD100, I suspect anything similar from Signature Plastics would cost 150 or 200, and have a 12 month turnaround)