I personally believe that I have been working in an Agile way long before that meeting in Utah when the Agile manifesto came out.
I recently found myself reflecting back to the 70's and my time in the Boy Scouts where we learned the patrol method. Basically, the patrol method is where individuals learn how to cooperate, lead, and follow others, where a small (usually six or less) group of scouts work together to perform tasks and achieve a common goal, and share the responsibility for the patrol's success. This is very similar to how Agile teams are constructed - the scrum master is truly the leader of the patrol.
The social dynamics of creating teams is the core of what makes Agile, and what makes Agile rock. Teams operate more efficiently and the team dynamic is one reason that Agile so efficient. I understand that there are other reasons why Agile is truly effective at reducing cost higher-quality, but for me it's mostly about how I learned to manage teams back in the 70's as a Boy Scout.
Lance Knight