Because in AGON's infinite wisdom the key to growing the sport of chess is not to strike where the iron is hot, and to hide it behind a paywall.
Although, to be fair, there is a certain logic in New York City, given it's chess history. But also it's such a cosmopolitan city, with people from practically every inch of the globe living there, that no matter who was playing in the world championship you're bound to have some ethnic/cultural interest.
Still, it's no secret that, as far as America goes, the eyes of the chess world are on St. Louis, not New York, these days.
Does anyone know why the South Street Seaport in New York was selected for the World Chess Championship? The Seaport has been known as a place for ethnic festivals and the like. Unless the championship was supported by tremendous media coverage, it would seem that the venue would draw few chess fans and be a difficult place for the players to engage in serious chess. The Saint Louis Chess Club seems like a lot better better option.
For the sake of chess, I hope it turns out well.