Walmart does stuff that is quite a bit more sophisticated than you imply, such as having quite a lot of inventory already in motion on trucks ready to be re-routed to where it is needed. It is my understanding that Amazon adopted some similar approaches to make sure it's regional warehouses remain stocked.

For that matter, Walmart certainly does ship in bulk (as in, whole trucks), but the contents of those trucks aren't measured only in whole pallets of items, but also smaller replacement inventory amounts (ie. when an item is rung up on the register, the system increments by one the amount going out on the next shipment to that store, which might be the next day, not to mention the amount being re-ordered from the supplier, etc.).

Not to mention that Walmart does handle a lot ofbretail e-commerce purchases that are shipped to individuals.

Oh, and Amazon at one point was poaching a lot of Walmart's top folks, so there was obviously something they wanted to learn: https://www.cnet.com/news/amazon-com-wal-mart-settle-lawsuit...

(Wow, has it really been 19 years? Damn.)

Anyway, the comparisons between the two companies are far from straightforward.