The Iyonix purchase gives the market impetus to continue to develop. It gives me access to USB and quicker processing and easier handling of large documents and images.
I know that to some extent these could be covered by add-ons to the RiscPC. However it is like making the decision to either repair or add accessories to your 10 year old car OR take the plunge and buy a new one to get the improvements.
If everyone (or a majority) kept repairing/upgrading their cars and few replaced them there would be little incentive for the production of new models. This is the problem facing Castle. Without support in the form of purchase of new machines the market will continue to wither and eventually die.
If you (any RISC OS user/supporter) are really interested in the longer term survival of the platform then your interest should be expressed in putting your cold hard cash on the table to purchase a new machine more frequently than once every ten or fifteen years.
Having dropped from a middle class income (++£) to nothing (- - £) I understand the constraints of finance for students, older and unemployed enthusiasts.