Hi Gurney, good point; the need to sell a balance of fuels still exists, but the USA uses a much smaller proportion of diesel fuel than European markets. I'm not 'USA bashing' here; fuel consumption per mile is almost double the European figure in the US, and it would help the US economy if this was addressed (not to mention the environmental issue).
A further issue is the globally decreasing availability of 'light sweet crude', which has a higher fraction of petroleum to heavier oils. Refining less 'sweet' crudes means more diesel is available, but the bias towards petroleum in the States means it is not economically viable to extract these heavier crudes for the American market.
We can't all use diesels, that's true; but there is huge scope for increasing the ratio between diesel and petrol. Biofuels are problematic, as there is potential to distort food production if this idea goes too far, but it's much easier to make biodiesel than it is to make biopetrol. You can also run diesels on used, filtered cooking oil; my local fish and chip shop does just that! (You can always tell when his car has gone past though...mmmm, haddock and chips!)
Tim