And that has always been one of the archilies heels of the f16 class, people bought new boats as early adopters of the class but 5 years on have invested only in new sails to remain competitive due to there being no new leap in designs within the class. Why spend a load of dosh when you don't need to remain competitive.
But with no one selling boats because there is no leap in design, there are few boats on the market for those who want enter the class at a discount unlike the F18 class and A classes where a few year old, now superseded design, can be bought at a huge discount.
So to enter the class you need to buy a new boat and few are willing to dip there toes in the water at a premium price. The class rules were ahead of there time but by setting good weight and build standards the consequence has been slow growth.