That's mutually exclusive - not in absolute technical terms, but simply how Adobe go about these matters. Instead of fixing AI from the ground up, they view GPU acceleration as a quick fix instead of tackling the actual underlying issues. At best you can hope that updating your system's graphics driver may improve matters, but otherwise it just is what it is. AI has always been slow as molasses in CPU-only modes. There's simply too much old/ bad code under the hood.