As far as I know, board positions are often filled based on explicitly subjective criteria, e.g. such subjective criteria might be: Who is currently on the board and what personality/skillset/experience does the board need in order to balance its membership? Who does the company & board need in order to: raise as much money as possible, be introduced to the desired go-to-market partners, look good to customers, [insert any other subjective criteria here] etc.

I am not aware of the concept of objective "merit" when it comes to board of directors appointments.

~corrected for bad grammar~