Three factors most people mention: a huge surge in competition, a different approach by Airbnb how is presenting its inventory (see 'Categories', perhaps it is spreading the demand more broadly) and/or the not-so-stellar U.S. economy (i.e. very low consumer confidence). Take your pick.
P.S. We have never (in 8 years) not be booked well in advance (1 year+), nowadays only 4-5 months; we are getting enough views and inquiries but one could sense the hesitation to commit too early.
