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take into account the cost a manufacturer faces with each redesign they make to a specific model. a lot of carmakers these days are facing financial issues(not just the American ones), and it's just much cheaper for them to introduce a redesign say every 5 years instead of every year. you also need to understand that up until the 1970's when the gas embargo happened, gas was incredibly cheap and readily available. the US was leading the world in engine technology at the time, and lots of people wanted cars with more horsepower. however, a number of manufacturers still made smaller economy cars at the same time like the Ford Falcon, AMC Rambler, Plymouth Valiant, etc so there was still a variety. about 40 years ago, cars were much more affordable than today and most didn't last nearly as long. because of this, just about everyone was getting new cars every couple years. these days, cars are more reliable and extremely expensive. it's not uncommon for some people(like myself) to drive the same car for almost 10 years before trading it in.

car manufacturers today DO have better technology and are far more efficient. take a look at back in the mid 1950's at the orignal Corvette. these cars had an engine displacement of about 4 liters, yet could only achieve about 140hp. i drive a '98 Integra which makes about 140hp, but the engine is only about 1.8 liters. basically, carmakers are always going through constant developments each year and further improving upon technology. if you honestly feel this way, you REALLY need to pick up a copy of Motor Trend sometime and see what's actually going on.

The gas crunch of the 70's did cause a major shift in American automobile manufacturing. It does seem like CEO's of the big three have a vested interest in maintaining dependence on foreign oil.

Electric cars have been around since 1900 and I've no idea why it's taking so long for them to become a staple in commuter life.