one nokia to rule them all
symbian is opensource and nothing can change that. as with every opensource project, there must be someone (person, commitee or bunch of people), that defines direction and developers that make it happen. developers might be payed by commercial stakeholders or by volunteers.
as of now, direction was decided bye board. board was chosen by corporate foundation members. these corporate foundation members also payed developers (there is very little of volunteer developers).
IMHO: if there will be not enough corporate sponsors, developers will be payed by nokia and nokia will as well set direction (without need for consultations with other foundation members).