They track categories How do credit card companies track your purchase categories?, and these are well established, but do they also track the item by UPC or some other convention, the quantity, the taxes paid, and the price per unit?
The store views your actual shopping habits as very important data. It lets them know what appeals to the various demographics of customers. They use this to target advertising, specials, and promotions. They don't want to give this data to the credit card company. The credit card company doesn't want to analyze this data, though if they did receive it they would try to turn it into a product they can sell.
The store might sell this data to the manufacturers so they can target their products, but would not want to have this data fall into the hands of their competitors.
The credit card company only needs to know the final amount, they don't need to know the number of items, the actual products, or the tax/tip/price split.
Any card vendor is sent the final line amount for authorization. They do not have the line items themselves sent over from the bill.
The category you talk about is the MCC code that is sent by the POS system that reads the card information: the vendor itself does not have special information or insight into your bill to decide what you bought.
If you buy a pack of cigarettes at Walmart, it will be categorized differently from the same pack from a Chevron POS (unless Walmart has a separate MCC code for its nicotine etc purchases than groceries and/or electronics).
I actually wish that some vendors had more information about my purchase as I like to keep track of my purchases in details but there must be reasons why it is not done.