You make a great point and I do agree to a certain extent. However, there have been some projects I've worked on where having a great manager made all the difference in the world. Having someone that deals with all of the non-technical minutia so that programmers can keep building stuff is really valuable IMHO.
Maybe software could fulfill this role one day, but as you say we're not there yet.
It may be that I'm getting too old and cynical, but when I hear arguments about eliminating the middle-man I can't help but think of a quote from Malcolm Reynolds in the show Firefly:
"About 50% of the human race is middlemen and they don’t take kindly to being eliminated."