Thoracic surgeons do a lot of heart surgeries, lung, transplants, etc. Their main goal is keeping critical patients alive, so they arent too concerned with the soft tissues that can be damaged when opening up the chest cavity (breaking ribs). They just want to keep you breathing or pumping blood. There is some generalizing here - may not be true for all Docs in this field.

This was told to me by the thoracic surgeon who 'claimed' to be able to do a 1st rib resection. Once he opened me up and saw the complexity of the Thoracic Outlet area, he was overwhelmed and closed me up again (after 4 hours of my arm in a metal clamp, the nerve was so mangled, it later had to be removed).

Vascular surgeons are more aware of the soft tissues involved. nerves, veins, arteries, fiberous bands, etc. And they are also more aware of anomalies, so they can deal with 'surprises' once they are inside.

This was told to me by my vascular surgeon, and also what I've learned from reading others posts and my personal experience.