During my research into participatory design, I found this question particularly interesting:
if we are all designers, then why is a design professional required in participatory design? Why don’t the lay-people just do it on their own.
From the book Sketching user experiences, Buxton puts forward that the role of the design professional, is to work with the users/customers/participants as a kind of combination coach/trainer, in order to help them come to an appropriate design solution themselves (The designer being more of a facilitator), in turn making everyone potential participants in the design process therefore acknowledging the richness of the design profession with the designer taking up the leadership role.
reference:
Buxton, Bill (2007) Sketching User Experiences: Getting the Design Right and the Right Design. Elsevier.