A project could be implemented in 2 ways: One, where all the groups and organisations concerned work as a team and share the responsibility and duties. And two, where One person assumes all authority through centralisation of powers. I believe the first option is a more effective way to get any project work done.
Firstly, team-work brings out the best ideas from all the members. When a number of people come together and brainstorm, they can come up with a number of ideas or effective ways to solve a problem or resolve an issue. Consequently, they can choose the best of ideas which would help resolve the issue better. Furthermore, they can also improvise on the ideas and develop them further. Such a process of idea development is possible only through team-work and an individual alone would not be able to think on such a wide spectrum of ideas.
Secondly, when people work in a team, they all tend to work hard and with integrity. This is because they all have a stake in the outcome. Everyone knows that they would all be credited for the outcome - Positive or negative. Everyone wants to be credited for good work and therefore, would work towards making the project a success in the best possible manner. Eg. When a consortium of companies comes together, their priority is to make the project effective and profitable. No company wants the project to fail as it would reflect negatively on each company's credibility.
Thirdly, in case of a centralised leader(person), a large proportion of the member groups/organisations in the project may disapprove of the leader's policies. When this happens, they might protest by not working towards the goal in the manner proposed by the leader. Even if they would not protest completely, they might...