THERE is no New York art world; there are only art worlds: a planetary system with no sun at its center.

Certain alpha institutions, collectors and pundits may dispute this decentralized model, but galleries tend to confirm it. There are many hundreds of them, if not thousands, large and small, throughout the city. Most are commercial enterprises. A rich, tiny handful has a ridiculous amount of power over what should be shared resources, like museum exhibition schedules and the attention of curators and boards of trustees. But most galleries get by the way we all do in this city, on work, budgets and luck. And they’re a bargain for art lovers.