The schemas for Amazon and Walmart's product information are absolutely bonkers and constantly missing features that they demand be provided.
Here's the XML Schema Definition for "Product" on Amazon [1]
This is joined on each of the linked category schemas included at the type, of which each has unique properties that ultimately drive the metadata on a particular listing for the SKU. Its wrought with inconsistency, duplicated fields, and oftentimes not up-to-date with required information.
Ultimately, this product catalog information gets provided to Amazon, Walmart, Target, and any other large 3rd party marketplace site as a feed file from a vendor to drive what product they can then list pricing and inventory against (through similar feeds).
You are right that the control McMaster-Carr has on their catalog is the strategic and technological advantage.
[1]: https://images-na.ssl-images-amazon.com/images/G/01/rainier/...
Here's the XML Schema Definition for "Product" on Amazon [1]
This is joined on each of the linked category schemas included at the type, of which each has unique properties that ultimately drive the metadata on a particular listing for the SKU. Its wrought with inconsistency, duplicated fields, and oftentimes not up-to-date with required information.
Ultimately, this product catalog information gets provided to Amazon, Walmart, Target, and any other large 3rd party marketplace site as a feed file from a vendor to drive what product they can then list pricing and inventory against (through similar feeds).
You are right that the control McMaster-Carr has on their catalog is the strategic and technological advantage.
[1]: https://images-na.ssl-images-amazon.com/images/G/01/rainier/...