But it's more than this. I think the real lesson is that a program is always a work in progress... like a walking person, always falling forward and putting one leg after the other to stop the fall. The moment you don't touch it anymore it dies.

"Working" can be a programmer writing code, or just a user putting data in, or submiting the occasional bug report... or anything. But the moment it stops interacting it gets out of sync with the world.