The rumor stems from a posting on a Chinese “microblogging” site called Sina Weibo, so be sure to take it with a grain of salt. If Apple decides to sell the iPad 3 at $579 instead of the current $499 price tag I’d expect the iPad 2 to stick around for another year.
Apple really likes that $499 price point and I don’t think they want to give it up for a year just so that they can put a Retina display in all of their models.