products are usually linked via facets and categories, it’s very unlikley there’s any AI inolved

AI graphs draw from the same well of data when making substitutions.

I asked ChatGPT if it could find me an alternative product for the given supermarket and it gave a load of sensible substitutions!

ChatGPT doesn't have live inventory data on the store's warehouse. It can give you recommendations for substitutions that a generic store might have. It can't give you a substitution based on a specific store's remaining inventory.

This isn't an AI problem strictly speaking. It is a retail strategy to fill orders and collect money in a way that maximizes revenue with limited respect for accuracy.

AI integration to a store's inventory data set just accelerates this process.