To be honest it may be more that those in Europe aren't looking for pure horse power as we seem to be wanting here in the US...living very well with the power of my "base" 4 banger 2003 Subaru Baja...
We don't have big blocks here in Germany. Compared to a gasoline engine, driving a diesel engine is much more fun (due to higher torque). More than 70% of BMW 7-series and Audi A8 are sold with a diesel engine. Even Porsche is offering diesel as an option for the Panamera.
Diesel engine is a nice combination of driving fun and fuel saving.