Perhaps they still need the chips for a while until they can migrate their hardware to other chips?
Except they just divested themselves of the division that does hardware based on other chips. Basically they sold to GF and probably required that GF would continue fabricate POWER for some time before renegotiating in a more traditional fashion. Maybe they are hoping that nVidia or some other companies will start designing serviceable POWER architecture chips and then they can sit back, and be like ARM without actually commissioning any actual chips and also sell servers based on the platform (or Tyan starts pushing out boxes they can slap an IBM logo on and skip designing servers either)
I think it's unlikely to go the way they are hoping for, but then again I never would have guessed Intel would have been able to get significantly into the Android ecosystem, so strange things can happen.