To defend the automakers a little, the concepts shown are not so many years out like the diesel hybrid cited in the Detroit News article. While diesel hybrids will be expensive, they are not impossible to make today. Also, if a car sparks real excitement at an auto show, it's often fast-tracked into production. So, yes Detroit News, there is a little green washing but also a lot of good ideas that are coming to the market very soon.
[Source: Detroit News]