Without a coherent, plausible, inspiring vision, a team default-diverges.

People aren't diverging on purpose, they just don't know what the vision is.

The path of least resistance for a bit of work will go in some random direction.

As everyone on the team follows their individual path of least resistance, everything tends to decohere.

But a plausible vision is like a magnetic force; things pull towards it unless they have a strong reason not to.

It becomes default-cohering.