First, Oprah announced that she was retiring from daytime TV in 2011. A few weeks later, Lance Armstrong announced that he was hanging up the bike helmet in 2011. On Monday, Miley Cyrus and Disney announced that “Hannah Montana” would be dunzo in 2011. Meanwhile, Tyra Banks and Simon Cowell can’t wait a year—both have said that at the end of this season of “The Tyra Show” and “American Idol,” respectively, that they are gracefully bowing out. So here’s my question. What’s up with people announcing their retirement three months to a year in advance? Is it for easy publicity? Or to make sure that their final season is thoroughly infused with over-the-top nostalgia? Or is everyone just wanting to chillax for a while, since the world is going to end in 2012 anyway?