Who needs a Project Manager?

All this talk about Flash Projects led me to an interesting question. Why do we need a Project Manager? Why can't projects manage themselves? I feel someday they will . Project Management is more of an art than a science today. Sure there are theories abound, but they are not as mature as say management theories. Once the theories get translated into software, will we still need the Project Manager? Remember we are talking about 10 - 30 years from now. Day dreaming? You bet.