Let’s call the history of Runequest from the Avalon Hill deal to the early 21st century “troubled”. Its history after 2003ish was…convoluted seems diplomatic enough, but at least there were versions of Runequest available, albeit not from Chaosium itself. I think there have been seven, maybe eight, editions of the game over the decades. Annoyingly the companies don’t seem to have used a consistent numbering system.
As for Chaosium itself, it underwent what was likely an excessively interesting process in which it essentially broke into component companies, and then re-accreted back into a unified body1. In 2018, Chaosium finally produced a new, in-house edition of their venerable RPG. Huzzah!
I’ve owned a copy since 2018 and at some point I really need to read it.
1: I would draw a parallel with a gas giant moon thought to have been disrupted by an impact, then reformed, but I can’t recall which moon that was.