I haven't seen a brand new F18 for a couple of years now other than at the F18 national champs where it was I think the Nacra dealers demonstrator. Would those same buyers stick with the F18's if a more modern class appeared and on the water was more fun to sail, I would suspect not.
You need to get out more. I was at a regatta in FL last weekend, of the 11 F18's present, at least 5 were less than one year old!