The fundamental issue isn't addressed but it sure is hinted at. Scheduling is an NP problem. As queue size, or backlog, or (insert thing here that tracks work to be done) grows it takes n^p calculations to schedule it optimally. This is hit on when it mentions small teams hitting their estimates. They can do this because their task list is small enough to go through all the permutations and actually come up with an accurate estimate. The only way to keep an n^p problem under control is to divide and conquer it. The leafs of that process must not go beyond a fixed size and the task divisions can't be recombined prematurely. Everything else is just yet another management idea that that will fall apart when the task has too many pieces. Once agile or any other management methodology acknowledges the fundamental mathematics at the core of things I may actually take them more seriously.