@mk yes exactly you are right i agree with you project leader plays an important role if project leader have not leadership qualities, then also other team member do not work properly.
Like many others have already stated, every individual or group of people involved in a project contributes significantly to its success, so it is difficult to say one is the most important. After first reading the question, I assumed the project manager would hold the most important role because without their leadership, structure and organization would quickly fall apart. However, after reflecting further, I believe the client or end user would be the most important. They provide the “need” that justifies the project’s existence. For example, if there is no patient need for a new medical device, there would be no reason to develop one. If a project continued without an actual end user need, the effort put into it would be wasted and the company would lose valuable resources and time that could have been spent on more meaningful projects. I think that it is crucial to obtain Voice of Customer feedback during the initiating phase of a project to be sure that there is a user need. If the project goal is to develop or improve a medical device, one way this can be done is conducting interviews or surveys with medical professionals.
When talking about the most important people with a project, I would say that all of the people are equally important to a project to it self. As I saw it was mentioned above it is like a machine in a sense that each of the parts are just as important and another. For starter with out team members the project deliverable can worked and delivered. Without a project manger, there will be no direction from the higher ups to the team members for what need to be complete. Without a client what even is the project being made for and same goes to the consumer and the things that they need. Then without the stakeholders and investors, where is the money going to come from to fund the project. With all these pieces the machine begins to work. Without one of the pieces the machine begins to fall apart and wont function correctly.