They didn't start Curtis Painter all year. Kerry Collins was named starter in pre-season when Manning was put on IR, then Painter from week 4 when Collins went on IR, then Painter was benched for the last 5 games for Orlovsky. Painter only started eight games, and was pulled in three of those.
Either way the point still remains the same, they started the season with a 39 year old QB who was 2-11 in his last 13 starts then went to Painter and Orlovsky who was a starter at one point during the Lions 0-16 season. I think it was blatantly obvious that the Colts were trying to be noncompetitive so that they could secure Luck.