This kind of fractal complexity is true per batch. The problem being described here is quite simply large batch sizes, with many projects treated even as just a single batch. The smaller your batch size, the more constant your overall project velocity is.

80/20 is therefore a sign of a poorly managed project (since visibility of true velocity is hidden, planning is impossible at best or based on false data at worst, and overruns are collected and unpacked only at the end).

Unfortunately very few managers involved in planning get this, and as a result don't recognise their responsibility is for delivering the whole at a predictable rate by managing this process. (Instead we often see a sick project management culture of not giving the client what they need and whipping the delivery horses harder, under the illusion that this is just how projects get delivered - always painfully and late, if at all.)