I don't think gas engines are going away anytime soon. In Europe, its important to remember that the only reason diesel got so popular was the cost to own one was less than a gas engine. People always talk about the high price of fuel in Europe but they don't realize its mainly due to the extreme high taxes on fuel they pay. Its very obscene. Europe is not like North America, Europe is congested with roads that were never designed for the vehicle traffic that is on it. Most places over there have excellent public transportation but for some reason people want to use their own personal vehicle. This another reason that the congestion has taken root. I have been to several countries in Europe and they definitely have that new car diesel reek. The Full size SUV will still be around, only much lighter, more plastic and not metal. Look at the Tahoe and Suburban today, The rear quarters are half plastic, the struts in the rear hatch are plastic, both the hood and hatch are aluminum.
Remember, the pickup truck is a vehicle that most predicted would be impacted by high fuel prices, yet it was not and thanks to marketing, has really taken over the lead in new vehicles sales.