That horse has already left the barn. The rest of the world is headed towards smaller less polluting engines and the Big 2.5, if they want to compete, will have to follow suite. Also, Ford Eco-Boost engines found in the F-150's and other models have a surprising high take up rate, so much so that they are taking advantage of the smaller engine sizes and designing cars with smaller engine bays in order to save space and weight. Ergo there's no way that any of the Big 2.5 are going to re-design their vehicle line-up to fit large displacement (V-8) engines (pick-up trucks excluded, for the time being).
Meanwhile, European manufacturers will keep pushing for better mileage cars which will be of great benefit when, not if, gas prices increase ( I don't know if anyone has noticed that despite low to flat cost of oil local gas prices have been creeping up). All it takes is for some world unrest, disaster, stupid policy or "tweet" for the price to jump drastically.