Planned obsolescence
"...parts in ...cars...might last and then wheres your job for life?"
I think this has more to do with the downturn in car sales than the economic climate. Cars just last longer these days, while remaining comfortable, reliable and convenient, and without the tender tinkering that the iron of old (pre-70s or so) needed to stay rust-free and without any knocking ends... So people don't feel the need as much to replace or buy new. Changes in tax breaks for company cars have also put a dent in the new car market.
It's not just about protectionism, it's about advancing development. The US manufacturers have had to compete with reliable, durable oriental imports, and even if they're not quite as good (they may be, I don't know either way), they're better than they used to be. If the average time that someone keeps a new car goes up from 4 years to 5, the number of people buying new cars has to go up 25% just to keep production at the original levels, more if you want growth.