68,
Your questioning of automotive styling evolution can be easily explained.
MONEY
When you are GM of the 50's and 60's, and own almost all of the car market, you can afford to do anything! Results: Fantastic, sculpted lines, powerful motors, all new cars every year.
When you are the GM of the 70's, you lose money in the oil crisis (because of those powerful motors), and have to scale back. The government gets tough on speed, and safety.
Results: Downsize, smart size, new size etc...Huge bumpers!
When you are GM of the 80's, the government is getting tough on economy, and safety, and the Japanese and european makes are comming faster and stronger, you play it safe, minimize platforms, consolidate, and reduce costs.
Results: Many boxy cars that look alike.
When you are the GM of the 90's, the economy improves, and you have some more coin for do or die efforts. The public has grown weary of tiny econoboxes.
You "rediscover" curves, and go nuts.
Results: Jelly-bean styling for everyone!
Now you are GM of the 00's, and you realize that people still want fantastic, sculpted lines, powerful motors, and quality to match.
Unlike in the 50's and 60's, you dont have as much market share, and cant afford all new cars yearly. Unlike the 70's and 80's, you have learned to intergrate safety and economy, with style and size. And a part of you wishes to forget the nineties.
You dont have much money, but you are determined to use your resources wisely.
Results: Boldness! Go big, or go home!