Small groups are getting bigger and merge with each other. Besides, if not, They were fighting each other, taking salves out of their wars. There should have been a way to organize the interaction between each others.
I really believe we are more fit in small groups and this makes the solution of small groups seems good one.
The problem with small groups is that they can't solve large problems. WE can't go backwards now, only forward so we have to find a way to carry the small groups into a future where they can communicate and cooperate effectively to face the global issues. A challenge to be sure.
Reorganizing large groups to smaller ones seems inapplicable right now, besides it had became impossible for individuals to compromise their individuality and freedom in order to belong to a small society that provides them with safety and stability. As you have just said we can't move backward.