You trade flexibility for that promise of efficiency. Since AWS prints money, Amazon-Retail could afford to experiment with stuff. For example, I'd argue that

You trade flexibility for that promise of efficiency. Since AWS prints money, Amazon-Retail could afford to experiment with stuff. For example, I'd argue that Prime Video hit the market a few years ahead of viability, when we were still in the "I have Netflix and it has All The Things" era of the market. Now they've got a ready-to-go platform and content while other players scramble.