Earlier quoted context omitted.
1988 would put this squarely in the 'Apple trying to convince Motorola to develop the 88k' era, most likely this was a backup plan in case they failed (they did, but by the time the 88k was killed off, they'd managed to get AIM founded and the 601 was 'in the pipeline')
There was an AMD 29000 Macintosh. But Apple execs were afraid that would piss off Motorola too much, and they still needed their parts. So then there was an 88k Macintosh. Execs decided that Moro didn’t have the volume to compete with Intel, so they put them together with IBM to form AIM and develop PPC (they considered HPs Precision RISC as well) and went with that until it was clear even those two couldn’t keep up…
Was there any serious consideration for an ARM Macintosh derived from Mobius, or was that strictly meant as an Apple II replacement and then canned in favor of Newton?