You need to divorce what Castle would like (10% of ARM processors running RISC OS and £8-10m investment) with what they've got (a dispute and no clear way of resolving it and responsibility for cancelling 3rd party licences and no product to offer them in place of their contract).
As I see it the 3rd party developers have little choice but to continue to market their current products 'illegally' - if they want to remain RISC OS developers. Castle cannot offer them anything other than an 'early' RO4 as they have no access to RO Select or RO Adjust. RO5 for legacy machines is some distance off.
If Castle don't offer them this way out then they will be directly responsible for destroying the RO market - although they would hold ROL to blame.
What's possible is a conundrum. Castle clearly don't want to accept that it's possible to go back on the legal letters they now admit to having sent out to the developers but, at the same time, they have no proposed solution - other than hoping ROL cave in.
Of course if it all worked out as Castle hope there would be a bright future for themselves (and RISC OS) and they maintain that they want (and need) 3rd party developers). Blocking the dream is ROL maintaining they have not broken their contract (according to the Drobe report) and Castle "We know we're right".
With luck for all a compromise will be agreed in double quick time.