I am not sure that I know or have a good answer.
It is also critical mass. It is also knowing that you can find staff, so if you have peaks and valleys in your demand, you can service those. Certainly labour rates play a role. It is a complicated business.
It is true that MRO tends to be more labour-intensive than manufacturing. That has to be part of it, but it is not the whole story.
We go back to technology and training. If you have a more efficient organization.... We can still compete with low labour rate countries, but we have to be competitive. The issue is that in our business there is no point in encouraging business that can't be globally competitive. There isn't enough domestic market to provide a demand for it. There is no hiding from global competition in the aerospace sector.