I wrote this comment earlier today, but didn't post it. Now I do, and added some stuff at the end to hint the answer to your question:

I worked for amazon logistics some time ago and the lack of future vision and aim for automating everything™ was the biggest reason for why I quit.

I wish amazon would invest more into automation, but at the moment humans are just so much cheaper that you’d rather hire 500-2000 people for a few months peak (prime day and holiday season), than invest in automation.

Actually, amazon itself does zero to none research and engineering in logistics by themselves. Instead, they only buy third party solutions (Opex) or the whole company (Kiva - now amazon robotics). And Kiva is only working on the six wheeler, Robin (arm) and Pegasus. What does this mean? Well, amazon has more than one warehouse type: they have the fullfillment centers, where the six wheelers are used, but they also have IXDs (inbound cross dock), where EVERY product, which comes from the vendor and will be sold via fullfillment centers will go through. These IXD facilities have almost no automation, at least the ones which I visited (UK, DE, ES).

People are counting hundreds of shirt buttons by hand.

People are bubble wrapping hoes for gardening by hand.

People are bagging clothes by hand.

People are repackaging STANDARD SIZE cans (food and drinks) into boxes by hand.

People are palletizing STANDARDIZED CONTAINERS BY HAND(!)

People are putting a single scissor into a tote, because the computer told them so. Why? Because someone entered wrong dimensions BY HAND. (You could easily get the dimensions by scanning. Even taking a picture would be sufficient to get the correct dimensions into the system). [1]

Kiva's projects don't solve a single problem regarding: Palletizing, receiving items, sorting items in the RECEIVING part of IXD, labelling items, bubble wrapping items, bagging items, repackaging items into new boxes (literally putting item from container A into container B). What made me sad is that amazon didn't even try to solve these issues. They just act like these problems don't exist and always show the nice fullfillment centers where you pick and stove.

To end my rant: Amazon was the worst company I ever worked for. Insanely slow, very inefficient and way too much nepotism. They lack the actual will and hunger for improvement. My main goal when I applied to amazon was to make an "all lights out warehouse". What I got instead was an enterprise which is rotten on the inside.

But hey, there were still a lot of brillant people, especially my manager (kudos to him!). Also, the engineers who worked for AWS were always very friendly and problem oriented (only had very little contact during outages though).

[1] A tote is one of those yellow boxes: https://media.wired.com/photos/593256d2edfced5820d0fb9d/mast...