I completely agree. I would say that the situation is sustainable if we are careful not to lose the whatever advantage we have and if we invest in finding new ones but also very tenuous given the global nature of our world today and the nature of the competition that is arising.

In case I misunderstood, I agree that losing the classes you mention could very well mean losing our edge in design and invention but losing spec work to factories in China is not a very good argument to keep those classes.