The owner is an idiot who has no clue how to put together a top flight organization. It all starts at the top and crap just trickles down.
Ex-Lions coach Darryl Rogers once said while coaching the Lions, "What does a guy have to do to get fired around here?" Apparently winning only 25% of your games over 6 years is perfectly fine. In fact, after 5 years of being the worst team in the NFL over that time frame, its so acceptable that Millen got a 5 year extension. Millen is also one of the highest paid presidents/GMs in the game. He got $3 million a year to join the Lions and I doubt he took a pay cut.
The fact that Millen kept his job is not surprising to the locals at all. Detroit is a huge football town that blindly supports this team. There is no real incentive for Ford Sr. to fire Millen since the money keeps on rolling in. Stupid decisions and losing go together with Lions like Hot Chocolate and marshmallows.