Its curious that selling to one's customer base amounts to an "echo chamber." The Amazon Echo could be really nice. If I could tell it to play an audiobook, I'd be very tempted. It's a truly new product in a world that has too few of those.
The problem with Amazon "selling to their customer base" is that they're doing the old "cheap razors, make money on the blades" shtick, because they're selling all their hardware at or near cost. So the correct measure of success is how many more blades you sell, not how many razors. The author is arguing that the low engagement after purchase due to poor quality undercuts how many blades they sell.
