Diesel engines why not more available in smaller vehicles ?

Diesel in small cars is popular in Europe, we have rented several diesel manual transmission cars and vans. All preformed great and got hand calculated 35 to 40 mpg driving like I stole it. The last van 7 passenger only had a 1.9 liter TD and had plenty of power.
Always laughed at the guy at the counter when picking up, had to explane that I daily drove a manual diesel in the states! Only real difference was shifting with left hand rather than right.