> customers will demand more efficient vehicles

The problem is those vehicles don’t exist, because the manufacturers only want to build the high margin gas guzzlers.

Look at fuel economy of US made vehicles vs those in Europe. It’s beyond a joke.

Whatever your standard is for an "efficient" vehicle, more efficient things than those 15-20mpg trucks or SUVs do exist in the US. Every automaker sells a serious car that gets at least 30mpg combined if gas-only, or like 50mpg if hybrid.