In my opinion, I will say all are important to the success of a project, we need a developer to have a project,we also need a good team to have an outstanding project and the project also need to be accepted by the community to have resounding success.
Sure, all may be important but at least you need to be able to have a quality team to be able to build a product and that is equally something that goes with the developers as well, since they are basically part of the team too anyway. How will you be able to entice and build a community, when you do not have a team that is rock solid and have a product people can believe in its long term.
Gone are those days when people invest into empty promises, these days, people need solution and real life product they want to be investing in and without that, community will not even come up, but with a good one, it is most definite to see community build because it is that community that actually makes up the success of the project in the long run.