Crosby was, is, and continues to be the face of the Pittsburgh franchise. He has accomplished at such a young age what even the great Wayne Gretzky couldn't do so fast -- went to two Stanley Cup Finals and won one; scored the goal that won Canada the gold at the 2010 Winter Olympic Games (thus becoming known all 'round the world); is the face of the NHL and one of it's most popular and we'll-known superstars, etc., etc.
A mega contract of that magnitude, while surprising to many considering Crosby's concussion issues, should have been expected, the mere fact that he'll remain a Penguin for the rest of his career.