I've been lucky enough to work over the years with some very smart, very capable people who were also fun to work with. In many cases, our skills and interests complemented each other and together we could do far more than either one of us alone. Having a good partner to work with is often more productive than trying to do it all yourself, especially since you can catch each other's errors earlier and suggest alternative approaches before wasting time going down a path that turns out to be wrong.
However, it's hard to scale beyond two. Heck, it's hard even to schedule a meeting with more than two. With three or more, you have a committee and "the patient dies on the operating table while the doctors argue" as one of my teachers used to say.
I close with a wonderful quote from Charles Kettering, who said this upon hearing how wonderful it was that Charles Lindbergh had flown across the Atlantic all alone:
"It would have been still more wonderful if he had done it with a committee."