Downsizing Detroit GM and Ford are shedding market share and slashing production. Their new cars are underachieving. Their supplier spinoffs are teetering. Detroit appears destined for a smaller place in the auto universe. This was to be a year of rebirth for Detroit's Big 2. But that's not what happened. General Motors and Ford Motor Co. have reached a tipping point. Incentives aren't working, new cars aren't generating excitement, and America's automakers are whacking production. The Big 2 are getting smaller.