See the problem is that while employees are being asked to bear greater and greater portions of the risk, they are not being rewarded along with it.  For example, you can reasonably argue that in a more flexible work force, it makes sense to move away from defined benefit pensions.  However, the alternative, 401k's are actually an inferior product.  Sure you get flexibility, and the potential to get better returns, but for the average person, they will have less money available for their retirement while living longer. 

If you changed the relationship between the big three and the unionized workers such that you exchanged flexibility for  a bigger stake in the company outcome, then maybe you'd have something.  As it is, when the company does well, the employees get to keep their jobs, and when the company does poorly, they don't.  So the UAW strategy has been mostly focused on mitigating the downsides, trying to make it as stable as possible