What you say is completely true for a spherical team floating in a frictionless void. The reality is that it is quite difficult to break products down into sep

What you say is completely true for a spherical team floating in a frictionless void. The reality is that it is quite difficult to break products down into separate features then work on those features separately and in order. Because of this, it's very easy for planning meetings to accidentally become "What did we work on last week? Will this still be done on time?"