I think that you and I have different opinions of what a desirable future for our platform is.
I would like to see a system that uses the best concepts from RISC OS (the GUI, typed files, simple application management) to free the power of cheaply available hardware, whatever the processor, and perform tasks I could never do with a RiscPC.
You, I think, are looking for RO(D)L or Castle to become a major player in the OS market with a return to the days when ARM processors were the most powerful desktop processors in the world. I think that's very unlikely to ever happen, especially the former.
"what RISC OS hardware manufacturer is going to risk their financial future when the user base is busily moving [to] x86/x64 and Linux ?"
Perhaps Advantage6 would still be producing the A9home as a spin off from other work, I don't know. I don't much care, to be honest. All (both) the hardware manufacturers are telling us that they don't make their money from RO desktop products anyway, so maybe they'd be better off without it!
For what it's worth, I don't think Linux is any of the things that you suggested (I don't even want it to run RISC OS, I want it to run RISC OS-like applications; the current OS doesn't get a look-in). I see it as a source of device drivers that it would take the remaining RO programmers a hundred years to reproduce, I see it as a processor independent platform that's unlikely to crash, I see it as a word that will make a couple of orders of magnitude more people than our current (desktop) userbase take notice (most of them will then ignore it, but if just a few like it, maybe they'll use it and it will have a future).