I think there were a lot of things in the way preventing progress...

1) Auto maker unions block new technologies stating it will obsolete their work force on an unproven technology.

2) Auto makers don't want to retool unless they can reap substantial benefits (hence the reason Chrysler never implemented the rotary engine on a domestic vehicle - they own the US patent since the 70's, but never put it in a car).

3) Reliance on oil gives many other perks which are not publicly mentioned, but put cash in certain people's pockets. (story on coal last night on the news about how efficient coal is and how clean burning it is, but then they go on to say the technology to make coal clean burning is more than 10 years away...)

On the side of GM, I like the direction they are trying to go, working on all fronts for fuel technologies. The bad side is they need to improve on reliability and quality. They have an impressive hybrid on the full sized GM SUVs that looks very promising.