Thanks. You saved me about 20 minutes to create a response to an argument that contains several flaws. I don’t have the research you do, but as a working professional in the ad industry, I’ve got plenty of anecdotes about how important collaboration is to the creative process.
One of the best branding projects our agency ever did started with me tossing out a casual joke about the product. Had I been alone, I would never have even considered this as a real idea. But my partner heard me, yelled “that’s it!” and then furiously sketched out a concept that ended up in Costcos and supermarkets throughout Southern California.