Executive Leadership is not a team task.
Working with executive management teams while simultaneously coaching and consulting executives on that team we see that many successful organizations are led by single person rather than a team, no matter the competency and talent of team members.
This single person has the power to move the company to flourish into capacity or constrict below capacity, this pressure is felt by the management team and everyone the company impacts.
Many senior managers know and feel the responsibility that the accountability and authority for decisions is held by the individual leader not by a team.