If you're talking about "one product" which you want to sell, then build Windows or Microsoft Office with 5 programmers.

    the communication and coordination isn't between 
    all 1,000 developers.

No, it's worse. Teams usually don't know what the others are doing, leading to broken, blocked or half-baked features and work duplication.

Here's an example: http://moishelettvin.blogspot.com/2006/11/windows-shutdown-c...

Having all those 1000 developers talk to one another would solve all problems, but this is a problem of scale which processes solve to a certain extent. Your opinion also highlights what's wrong with software development as a whole -- you seem to be under the impression that you can go and hack stuff in a vacuum, without interacting with others.