> European & asian lightweight creations are utterly destroyed in even a minor accident
Yes. That's the point (something seemingly lost on the American car industry). They are designed to fall apart. The energy dissipated in that falling apart is what saves the people inside. If the lump of iron you are driving stays in one piece that means ALL of the energy was maintained resulting in a bigger bang for you. That feeling of safety is entirely false - just like the feeling of safety that comes from gun ownership.
Anyway, in answer to the original question, there is a pretty good reason why we all drive cars with 4+ seats rather than 1 or 2. We occasionally need to carry more than 2 people. That means either owning a car with enough seats for your maximum usage requirement or keeping a bigger, more expensive car, sat idle on the drive for the occasions you need it. That's damned expensive and not very environmentally friendly either.
It's just like the argument against wind power. Yes, wind power CAN provide X amount of energy. But, it doesn't meet your requirements ALL the time so you need to have backup sat idle which is very expensive and out weighs the benefits you were aiming for.