There's always been export diesels, Jeep Wranglers for example.
Someone in power has always been trying to keep diesel vehicles out of the U.S. Market (minus fullsize trucks with large diesel powerplants that could tow a train car). When Chrysler canned those dealerships and they switched over and were going to import Mahindra Trucks and SUV's with 4 cylinder turbo diesels....somebody stopped them from entering the US market.
I'd love to get a Toyota pickup with a turbo diesel, and enjoy a truck the rest of the world gets to enjoy.
A "Performance Diesel Car", the market has always wanted a 4 cylinder turbo diesel truck but they won't allow them to be imported.