The logistics buildout is arguably Amazon's biggest retail lynchpin.

However, it's built on a few fragile external costs.

First that comes to mind, is the comingling, which will theoretically resolve one way or another with their ending of comingling. Comingling almost certainly lowered logistics costs however...

Second being, the externality of how both warehouse and delivery workers are treated in the name of the almighty metrics. NGL I feel like the public's acceptance of their labor practices has ironically only accelerated the erosion of labor rights and worker treatment.