I've refrained from jumping into AIX & RT/PC discussions on TUHS. It seems more appropriate to summarize AIX history than try to correct or clarify specifics out of context.
I wrote about 5 pages, got feedback, revised accordingly, and posted at
https://notes.technologists.com/notes/2017/03/08/lets-start- .at-the-very-beginning-801- romp-rtpc-aix-versions/
Charlie