@AMS: I probably fall into category 3 (although I still care about RISC OS, I hardly use it anymore). However, I also own two well-working Omegas, a Kinetic-RiscPC with 256MB RAM, 2MB VRAM and RISC OS Select 3 (4.39). However RISC OS could not fulfill my computing needs anymore: professional HDTV video- and sound-editing, plus broadcast-quality 3D animation. So I eventually transferred my data to VRPC-Adjust on my PC, put my native RISC OS hardware in a big cardboard box and put them in the attic. I would have done that, wether VRPC had been available or not, because I don't have unlimited space and not the time to look after more than one personal machine. So VRPC allows me to keep in touch with the developments on the RISC OS platform, and gives me an excuse to purchase updates for some of the software packages I own, even if I don't use them much nowadays.
I will come back to native RISC OS, when (if ever) it gains the capabilities to fulfill at least some of the things I require from a computer.
@Peter: I agree, and RISC OS is quite a lot bigger and more complex than its applications. Also it really was Pace who did all the 32bitting for RISC OS 5 and the compilers, probably with a much bigger team than RISCOS Ltd. And it still took several years before Castle could use it in their Iyonix PC. All of wich IMHO just adds to your point, that converting the OS to 32bit-mode is a big task.