The cost of production for US automakers was considerably higher than that of foreign manufacturers, even those who assembled cars in the US.
The 2007 UAW-GM labor agreement established a two tier wage system that has had very little impact on hourly labor costs. Any UAW worker furloughed as a result of plant closing had right of first to return. Today, GM's unfunded pension liability is higher than it was when it emerged from bankruptcy.
I think you've strayed way off the reservation here.