Detroit is interested in meeting customer demand, nothing more. For the last 20 years or so, more customers have been demanding vehicles like minivans, pickups, and SUVs than econobox vehicles. Face it, there are already cars on the market that get 40+ MPH like the Aspire (what does it Aspire to be, a real car?). You can go to any number of dealers today and buy an econobox. Why do you suppose there aren't very many of these vehicles on the road compared to bigger vehicles? Simple - the majority of the customer don't want them.

This can change, sometimes very quickly. Following the 1973 OPEC oil embargo, gasoline prices doubled practically overnight. At the time, it looked like gas prices were just going to keep on going up. Very quickly, people became interested in vehicles with better gas mileage. At the time, the most fuel efficient American cars on the market were the Vega, the Pinto, and the Gremlin (winners all). Suddenly, those cars with funny names like Toyota, Datsun, and Honda became very attractive. They quickly gained in market share at Detroit's expense. It took several years before Detroit could respond to the change in demand.