Oh, there are many reasons we have large organizations, and one of them is that you simply cannot do some things with a small team. I think you have to bend the definition of efficiency to it's breaking point to argue that producing 15 widgets with 10 people is more efficient than producing 10 widgets with 5 people though.

A Honda Fit is clearly a more fuel efficient car than an F1 racer. This remains true whether or not the problem you are solving is "win an F1 race," which would necessitate using the latter.