AMZN ain't making its profit selling books and toothbrushes.
It's all the yummy egress and all the other markups you're paying for.
Who are all these people egressing gb/mo/customer? Does everyone except me work at Netflix?
I agree it's a weird thing to obsess over. I have never seen egress mentioned, let alone approach the leaderboard in terms of costs.
I'm not sure I believe it, but they could reasonably make profit on economies of scale that individual organizations wouldn't get managing their own hardware - merged hardware utilization, sharing engineering efforts, standard hardware procurement, etc.