he’s eventually going to make sure abandoned instances have admins
I think he meant magazines on kbin.social in this context. I don't think he has any way to control another instance and change who runs it, besides a kindly worded letter.
I do try to keep track of kbin instances and how up to date they are and their admins, but I can't really advertise in their place. One thing I've kind of been thinking about is it'd be nice if nodeinfo had information next to current user count of like: desired user count, max user count. Otherwise you have no idea what an instance admin is hoping for, whether it's just their personal instance or they're willing to support tens of thousands of users. Without that I don't want to send people to x instance and suddenly the admin being in for a surprise. But I just looked up nodeinfo and it looks like there's plenty of worms in that can about it being too complex already, so maybe I'll avoid opening my mouth about it... for now.