From the perspective of a student who got out of high-school, I got most of my work done in medium-sized group of individuals who actually wanted to work.

Any more than 10 was useless and they began to chit-chat. Much fewer and people tended to make mistakes or forget things. Those 10 or so people could be paired off into 5 groups of 2 for practice of exams, or 3 groups of 3 (with one floater, or one group of 4) for more round-robin type work and collaboration.

There is very much a reason the philosophers of old had a set class size of ~8, and why classrooms encourage "smaller" groups. The workplace should, in theory, value this more. However, in the sense of being "new and hip", I fear they've abandoned productive work to create "ideas".