Here's another view of the motor issue.

Didn't GM put Turbo chargers in the Prototypes? Why didn't they make it to production? Seems that the power issue would have been curved a bit keeping the turbo or super charger in the lineup?

As for the diesel issue, I think it will require one of two things.
1) the market to change for diesel, requiring the companies to change
or
2) the companies building diesels requiring the fuel stations to now market it forcing the car buyer to change.

The average Joe, probably has no idea what's in his vehicle. From first hand experience with drivers, especially in a "ME " generation market like NY. These folks have absolutely no idea or desire to know what the prime mover of their car is. They just want to put the key in the ignition and go.
Sad, very sad. But this is the source for marketing info.