[LenS]

Honda and Toyota went ahead with hybrids when Detroit decided to hold off because of the difference between the home markets in Japan and the US. Gas is much more expensive in Japan plus there's a sizeable market for much smaller vehicles among Japanese consumers. So it made sense for Honda and Toyota to pursue hybrid development. Though, Detroit probably should have pushed on it more because:
1) Such development would challenge their engineering staffs;
2) Much of the work into hybrids will probably be useful in other fuel efficient designs down the road;
3) Other markets are similar to Japan with higher gas costs and bigger markets for smaller cars;
4) Detroit should never have assumed that low gas prices would continue indefinitely;
5) For an industry that once flourished on selling cars on intangibles, ignoring the potential of greenies wanting to "save" the environment was a bit silly.

[supercat]

Though, Detroit probably should have pushed on it more because:

I would favor the development of three other technologies:

1. Variable-displacement engines
2. Power control using variable delayed intake closure instead of throttling (gives the Miller Cycle's advantages at lower power levels, while allowing more power when needed)
3. A five-cycle mode of operation when cruising (another freeper posted a white paper here some time ago; on an inline four, during low-power operation, the inner two cylinders would be used together as a double-sized "compounding" cylinder for the outer two).

I would think these would improve efficiency as much as would hybrid technology, but at lower cost.