The article itself says this, but the original idea comes from the military, not GM. Silos aren't functional; they're mission-based. Each unit down to the squad level is capable of operating in an entirely self-sufficient manner, but the scope of mission it can accomplish alone is smaller than higher-level units. This is accomplished in part by having all of the functional specialists you need in the units together with each other, instead of having functional silos. It's the original matrix organization, where you get assigned some functional specialty and your career is managed by that in terms of what you're required to learn and master doctrinally, and it also determines your unit assignments, but your chain of command is orthogonal. Your career manager has no say in what your mission is on any given day.

Somehow, it seems like the military is still the only organization to really get this right, but they of course have at least two pretty serious advantages over private organizations:

1) The personnel can't quit

2) They actually get training budgets and dedicated schools and enough slack in headcount to send people away from their units solely to learn their profession and then go back to the units