In other words, this problem was caused by a progressive regulation intended to help the environment that had the exact opposite effect intended. They set aggressive targets for MPG that were not able to be reached and still produce a car that people want to drive.

Remember the tiny Ford Ranger or Chevy S10? If they were produced today, they would be expected to have a very high MPG, which would require an engine unsuitable for the task as a truck.

The end result is that vehicles are forced to be unnecessarily large to get put in the class where low MPG engine can be installed.