In other countries, diesel is cheaper than gasoline (it is not taxed as highly). Diesel emissions are much more lax than gasoline emissions, and there are displacement limits. All of these things make diesel cars/trucks much more cost effective than their gasoline counterparts, so it makes up for the higher initial price. Plus, the initial cost is not alot higher because they don't have the US's draconian diesel emissions regs.

You want more diesel engines in the US, get the government to stop changing the emissions regs every 3 years. Very few OEM's can comply with this, and make money doing it.