I think that is the achilles heal of f16...not enough boats out there.
Round and round in circles we go.
Yes, F16s are not in the same league as F18 or A in terms of fleet size. For some people that is a critical factor. For others it is not.
For me, there's a whole bunch of more important factors that mean F18 or A is not an option for me at the moment (I used to sail F18, and enjoyed the quality and quantity of the racing). I hope that F16 fleets will grow, but even if they don't, I still won't go out and buy an A or F18, because they don't meet my needs in other respects.
So, lack of other boats may be a critical factor for you, but it's certainly not the "Achilles heel" of the class.
Paul