THE SHORE.--From what we saw in a recent pleasant drive along the shore, we infer that the Long Island houses are "patronized" this season about as well as any other region. Indeed there is great complaints (sic) that the travel up the Hudson and on the great rail road lines has been unusually light, and that people do not move about so freely as has been the custom. On the Island, however, the houses are generally full, and some of them are packed. The houses at Fort Hamilton, the Bath House, the houses at Coney Island and every where else in the vicinity of New York are filled with the joyous and the gay ; and are centres of life and attraction, of animation and bustle, such as we seldom see, even when sickness and gloom do not hang so heavily over the land. Indeed these are glorious places to spend the summer months, and those who go chasing after pleasure over long lines of railroad and through distant gorges of mountains would be far more likely to find it on the sea girt shore of our own elongated Island.
--Brooklyn Daily Eagle, Friday, Thursday, August 16, 1849 (and other days)
So reasons for the lack of Coney Island articles in 1849 seem to be a combination of the epidemic in New York (see Cholera in Nineteenth Century New York) and perhaps the Oceanic House's closure. But it's unclear that patronage at Coney Island was down (except due to fewer rooms available)...could be one of those instances when the news is sober so they don't want to report more cheerful/frivolous topics.
The Cholera in Nineteenth Century New York site notes that people who could afford to flee the city, did. Coney Island would probably be a good place to flee.