Are we talking "rent out a whole house" Airbnb listings, or "rent out a spare basement apartment" rentals?
For the spare rooms and apartments, I guess it's possible that a few rooms that would otherwise be rented to seasonal workers are being rented out on Airbnb. That said, I don't think OBX is the sort of destination that attracts those types of travelers, the young, independent, small-group, budget-conscience traveler..at least not like you'd see in Asheville or NYC. This is more of a family destination and not too many families are looking to crash in someone's spare bedroom for a few days in a off the beaten path residential area.
I think the Outer Banks is a little different. Based on my observations on rental rates for whole homes, weekly rental rates take a pretty significant dive for smaller homes farther away from the beach or sound, and demand drops way off on the shoulder seasons. When you factor weekly cleaning and management costs, a long term renter seems much more attractive.