I can confirm that. Amazon is doing it better than most others, for sure, but the effort and complexity is still there. And I'm not sure if looking up tables directly in some database (the Amazon way) and entering data through some cobbled together web interfaces (again, the Amazon way in some cases) is better UI than whatever SAP is providing. I know both, and at least in SAP everything is one place.

while true, any big business has a significantly easier time with logistics because they inherently incentivize vendors to conform to their standards. customer service will be the best available from these vendors as well

Yes they are ultimately responsible for all the same border crossing paperwork and such, but that is a lot easier when everyone you work with is giving you information in convenient formats and returning your calls quickly. Not to mention the ability to leverage work from past shipments as reference.

a small player in this space has a significantly harder time since they have less reference, and vendors are more likely to treat their business as a nice-to-have instead of a want or must-have.