Well there is a couple of things to consider there, one of which is that WalMart has everyone on its payroll between you and the product. Amazon does not. In particular Amazon doesn't count vendors who just selling through their platform, (they would be part of buyers/stockers at WallMart) Amazon doesn't count any of the delivery personnel for things like OnTrak etc. And at one point I thought the warehouse workers were actually subcontracted through another firm but I may be mis-remembering that.

Thus from a business perspective you get rewarded by keeping workers off your payroll, but I don't think it means people aren't working for you. The poster child for this is the 'sharing/gig/slaving' economy type places.

Because of that I am not convinced there is actually less human capital in moving the goods through Amazon or Walmart, but I do agree its accounted for differently. And that means I really can't agree with it as evidence to support the claim that humans should work fewer hours.

It would make for a great paper, maybe even a nice book, on comparing how many hours of labor are invested and how many people in getting a product from manufacturing to your hands using the two different product flows (and doing that for a representative sample of all products offered).