Why don't we put small diesels in most vehicles? Because we have relatively cheap gas, think diesels are like 70s oldsmobiles, and big cars = big profits. And oil companies are buddy buddy with the govt.
Think about any old style ranger/s10/toyota/etc, say, from 10-15 years ago, when they were actually compact sized trucks. Think about one of those with a 2.0 TDI type motor making around 140hp and 240ftlbs of torque. I think that would have been a popular option, compared to all the people who bought the 2.2-2.5 liter gas 4 cyls, and should have got at least 25-28mph highway.
Why was that never sold here?