Fria Ligan solved the chicken and egg problem by producing really compelling setting driven games but all based around there own core system. The system itself is barely mentioned in the promotion, it is all about the setting.
From a sales point of view you can produce unlimited numbers of books and never suffer rules bloat if they are setting or adventure books.
Yeah, but that wouldn't work for ICE, whose core products (with the exception of SM: Privateers) are setting-free rules systems. If they went the Fria Ligan route, they'd have to develop a totally new concept from the grounds up ...
I believe HARP would do well to re-awaken Cyradon, get some material out for it from the start (as seems to be the plan), keep up some output, and if that sells moderately well, start working on another HARP and/or RM setting with a different atmosphere - maybe something more low fantasy, or more Sword&Sorcery, or Science Fantasy.
One of ICEs strengths seems to me that it looks to fantasy literature for inspiration - if I understand it right, Cyradon had some inspiration from Diane Wynne Jones, and Folkways seems to take a close look at works by Gene Wolfe and Robin Hobb. Apart from straight adaptations (like Cubicle 7's Tolkien-based "The One Ring" or the upcoming Witcher of Expanse rpgs), there are actually not a lot of fantasy rpgs that do it like that - most have become very self-referential, being more inspired by rpg/computer rpg tropes than by literature (Green Ronin has been a laudable exception recently with their Blue Rose rpg, which is also very much fantasy literature inspired).
So I'd say work with that - look towards new and original works of fantasy literature like N.K. Jemisin's Broken Earth series or Sofia Samatars Olondria books, or Peter V. Brett, China Mieville, Jeff VanderMeer or (how I would love that!) to the very underappreciated weird fantasy author Zachary Jernigan and get inspired. Don't do a straight adaptation (most literary worlds actually don't work that well for rpgs), but have a good look at the elements and tropes of modern fantasy and get inspired.