The Chicago art fair used to be one of the premiere art events of the year. “But in the last five years, Art Chicago, which continues through Monday at Navy Pier, has been in what several observers describe as a steady decline. Many high-profile dealers, along with the art-savvy (and deep-pocketed) collectors they serve, have abandoned Art Chicago for newer, flashier fairs in Miami, New York, London and Basel, Switzerland, that are widely perceived as fresher and more innovative.”