The role of an able leader in the development of any organisation is as important as the oxizen to our body. It's just one leader who can make or mar an organisation. There are plenty of examples scattered around us to support this.
When India was born and Nehru became the first prime minister, his aim was to make India a country worthy for her people. He along with others created a democratic and secular government, created public institutions with broader purpose of serving the people of nation, gave people of the country equal opportunity, created equality among people of various religions and social strata among other things. He set out in creating a modern India by building dams, core-industries, higher education institute, etc. which were clearly meant to take India into league of leading nations of the world. Nehru had long term vision with which he acted for india. That is where the foundation for today's vibrant India was laid. Had he went the otherway of fulfilling his own short term gains, India would not be in position where it's now. Here the leadership of a single person Nehru was very important for india to follow either the path of peace and prosperity or the path of chaos like many other countries.
Similarly Tata group was just languishing and stumbling along in early nineties when Ratan Tata took over it. At that time hardly anyone would have thought that Tata group would be so globalised that it'll take over companies around the world. But it was sheer leadership and the vision of Ratan Tata that Tata group is where it is today. It's one of the most globally diversified and most ambitious diversified group from India. This success is again simply due to the vision of a single leader Ratan Tata.
Obviously, in all this we can not deny the fact that every leader needs to have an able and supporting team which can turn the vision of a leader into reallity. But here again it's the leader who selects his team.