I don't know about the 200 mpg carbs and other technology thats suppose to be stowed away. But something I have noticed over the years is that if one person can invent or discover something then someone else can (and will) as well. There have been very few inventors that hasn't had some one right on their heels that would have discovered the same thing. So if GM or an oil company has a new super battery on the shelf they can't expect it to stay there long till someone is making money off the idea. Or if they patent it there will be a dozen variations that are trying to working around their patent.
IMHO everyone is looking for a single sliver bullet that will solve all the problems of our time. I'm not saying it can't happen but don't count on it.
Specifically on the batteries I understand that there are some higher energy chemistries but the trick is making them safe. Think about a gallon of gas will take you 30 miles, now we want to but 200 miles worth of energy in a box the size of a bread box. The energy density is a lot higher, sounds difficult to accomplish to me.
