It's no coincidence that Amazon calls a unit of storage space in its FCs a "bin" and also happens to pseudo-randomly distribute products in the FC. I am convinced that Jeff Bezos' long term plan is to automate everything, and treat every problem like a CS problem so your CDN analogy is spot on. Pricing is automated, ordering is automated, and I'm pretty sure with Kiva storage positioning is dynamically optimized too. [0]
The thing is, the further invested Amazon is along this path, the cheaper and more profitable it becomes to continue. Moreover, the harder it becomes for new players to catch up.
Will be interesting what the plan is with these planes, I note Amazon also is investigating entering the shipping industry, a space pretty ripe for disruption[1][2]
[0] http://m.youtube.com/watch?v=UtBa9yVZBJM
[1] https://news.ycombinator.com/item?id=10907163
[2] http://www.bloomberg.com/news/articles/2016-02-09/amazon-is-...