I think this is my first thread with a subtitle. Title and subtitle pretty much say it all. I played for many, many years without once thinking about buying a starbase from AI player. The new Administrator mechanics combined with the serious scarcity of durantium on mid-to-late-game very large maps made me start doing it. Lots.
I don't dig into the XML or read lots of threads from maximizing players, so I don't understand much about the relationship status functionality. It just seems illogical to me that an AI would accept an offer to purchase a starbase when the mechanics were going to promptly increase its dislike of the buying player.
Aside: Please chime in if you have seen AIs buying starbases from other AIs. I've never had an offer for one of my starbases (or ships or colonies), but I've not yet tried to look out for starbase transactions among the AIs.