Why don't American cars last as long as Japanese cars?

My family has owned a Ford Taurus and a Nissan Altima of similar model years. Both cars are still running, but the Taurus has very low mileage (it's a 1999 with only 85,000 miles) and the interior is in horrible condition and the plastics Ford put in have been known for breaking. None of this has happened with the Altima, even though it has more miles. Why?

When japanese cars started to take over the world, they had the benefit of cheap labor and a more efficient build mentality. Rather than offering many optional extras as american cars did, Japanese had a simple model of using trim levels. You could have the base model, the upgraded model or the top level model of a car. That's it. American cars had a lot of customization. You could choose the engine, gearbox, interior, exterior and other features.
this meant that japanese cars could be mass produced a lot easier and faster and enjoyed the benefits of scaling production. Japanese manufacturer labor was also much cheaper. They didn't have to pay their workers as much nor deal with unions where american manufacturers did. More expensive labor meant that to remain competitive, american cars had to decrease the quality of build materials and processes. In reducing these costs, product quality suffered quite a lot. Combine that with the fact that the fuel crisis of the 70 and the traditional american car which was large and heavy with a powerful V8 engine was not as attractive to buyers anymore when smaller, lighter japanese cars could provide much better fuel economy.

anyways, as time went on, these effects lingered and you can still see some of them today.

Maybe you should take better care of your vehicles.

The Altima is about as Japanese as enchiladas; they're built in Tennessee or Mississippi. The question you should be asking is "Why was this Ford so utterly godawful?"