sorry Dom, have to disagree with you.
The position of Captain involves taking RESPONSIBILITY for the flight (the aeroplane, crew and passengers), any decisions made and, effectively, being responsible for any mishaps/errors which occur. From a legal perspective this opens the individual up to, potentially, large penalties.
Achieving the position of Captain, requires demonstrating a higher standard than that required from the FO standard (REQUIRED). There is a substantial difference to the job requirements of a Captain (PIC) and the FO. There is already enough of a move in the industry to reduce the Captain's position, relevance and status.
Captain pay should reflect this extra burden and should be a LOT more than it is.