I mistrust people, too.
And to get back to the OPs question, I think I agree with the AAO-HNS notion that there willl be a high demand in the future for ENT doctors, in general. There are a ton of jobs available in private practice and hospital based practice.
I can be difficult if your life needs (family) pigeon hole you down to a specific location that is saturated (usually bigger cities, and more specifically nicer areas within bigger cities with good payor mixes). It might even be worse in a smaller city that is saturated, again usually nice areas with insured patients (doctor heaven) - trying to be the 5th ENT in town, when the 4 that are are there are just getting by, but love the area and don't want to leave. However, the pharse, "there is always room for the best on top," applies, so you just have to tailor your competitive nature to make yourself marketable and desirable in the area you want to work.
Regarding subspecialties, some of the subspecialties have general population figures they have come up with. I think for neurotology, it is about 1,000,000 people per neurotologist? Some of the fellowships like peds, rhinology and even facial plastics don't neccessarily put doctors in to a position of practicing totally within their field, i.e. they may do a portion of their subspecialy in their practice, but continue doing general ENT, as well. This makes it difficult to really comment on the specific need, although, I am sure those subspecialty orginizations have some figures. I can't really say much about laryngology or head and neck, either. It seems like in residency, I had the impression that there is a very high demand for head and neck, but, getting out in private practice, in a catchment area of about 300,000 people, I really don't see a whole lot of head and neck cancer. Certainly not enough to support a practice.