Bookworm, I agree that in retrospect it seems a pity to my (non-tech) eyes that a 1090ES-based Flarm system was not developed, but we are where we are; it wasn’t. Maybe to do with easy marketing without official certification? Dunno, but there we are.
Glad you agree that, even without 1090ES, at least it helps with some categories of collision.
Regards – Chris N.