I think there is a lot of room for improvement in engine eficiency using turbo and supercharging or even both.

Hybrids and alt fuel are undoubtedly on the way but not in the next 5 years. I don't need to know about secret area 51 technology etc to know that. It's plain economics, motor manufacturers need a few years out of a new model to make it pay. Too many new models coming out at the moment. Watch the industry, when new products start to slow and all you see are facelift cars, that will be the signal that petrol / diesel cars have had their day.