Maxon will not release ProRender for Prime, that much is clear at this point, because it wouldn’t make sense for them to allow high-level new features to become part of the basic Prime package. They need users to have reasons to buy into the more expensive versions.
C4d users are getting the short end of the stick: with Max, Blender, SolidWorks, etc. the instant AMD releases a new version of ProRender, users can update to that version. Not so with the C4D version: Maxon keeps strict control, which means that C4D users will have to wait until the next major new version is released, and pay double to gain access to a production-ready ProRender.
The current version in C4D is only a half-finished affair, and barely out of alpha in my opinion. I compared Blender’s integration with the one in C4d 19, and I can tell you that ProRender in Blender is not only production ready (for stills at the very least), but that the integration is far better and actually simpler in use. And Blender renders MUCH faster than the one in C4d (same settings, same scene).