Why is that? Well according to Reddit (fwiw), the fees are making Airbnb unattractive: Why Airbnb Isn’t Worth All Those Fees, According to Reddit
If you are convinced and need a hotel to stay in NYC, I recommend this: Best hotels in New York | Telegraph Travel.
Lots of information on hotels over at The Telegraph. Well worth a look. You can find places at all different price points, at all different parts of the city.