Oil refineries are nowadays complex factories that convert crude oil into lots of different distilled products. When you process a barrel of crude oil, you're not restricted to some proportion of gasoline, some proportion of kerosene and diesel and whatever. You can basically turn it up to produce more gasoline, or more diesel fuel, or whatever. The losses aren't significantly different.
You can get more gasoline out of a barrel of oil, but you can also get more mileage out of a litre of diesel than litre of gasoline. Diesel has higher energy content.
What's more, diesel fuel can be made from biological materials as well. In fact, we have had people drive their diesel cars with discarded frying oil used in hamburger restaurants to make fries. You have to filter it, and you won't make the current EU emission standards, but for moving a vehicle, it works all right.
Whether it is feasible to move all or most cars in the US to use diesel is then another matter. Diesel engines are a bit noisier, for instance, so someone might object that.
But the everyday driveability of a car with diesel engine, particularly a modern one with turbo, is nice. Lots of torque on low rpm's so it's easy to drive.