« The unknown variable, Che Guevara theories applied to agile teams

In Che: Part One, Ernesto Che Guevara states:

In War and Peace Tolstoy remarks that military science assumes that bigger armies with more men wield greater force. 
On the other hand, only vaguely, do they recognize that during military combat the final strength of an army is also its true physical capacity multiplied by one unknown variable. 
One unknown variable. This variable is none other that the spirit of the troops measured as their greater or lesser desire to fight and confront danger. 
Men with the desire to fight who also understand why they are fighting regardless of who they are fighting whether under military geniuses or those of normal intelligence fighting with clubs or machine guns that fire 30 rounds a minute these men will put themselves in the best positions and so they will win.

Immediately after hearing this I’ve started a comparison with agile projects.

It’s obvious in these days, with agile becoming mainstream that bigger armies (expensive tools? costly hardware? costly solutions?) and bigger teams don’t imply success in software development.

What is then the unknown variable in an agile team? 
I would compare the physical capacity with the knowledge base of the team, with the general collective intellect. 
The desire of fighting is nothing else than desire of success and play with risks and issues in a project. 
But then, it’s in the understanding of the why they are fighting the most interesting part.

I’ve seen teams over-performing in few different situations: some were strongly committed to the success of a startup, feeling part of it (my experience at Fluidtime), some other were committed to reach excellence (a common behavior at ThoughtWorks).

The why can be different from team member to team member, some people need to feel that they are part of a whole, some others need recognition and differentiation. 
Some others are carrier driven, some others have a strong desire to learn, improve.

Finding the right motivation in your team members will make your team run faster and smoothy, the unknown variable will boost your speed and quality.