I may be able to help here since I worked as a data analyst in the grocery world. I believe "retailers innovate at the front end" refers to the store specific details that are created by giving individual stores some freedom. For example, a product may be required to be on display at the front door of a store but store and category managers are given the freedom to choose which item it is. Big football game coming up near a NFL city? Maybe chips and soda.
As for packing, price, and promotions, it does have a bearing on how inventory and sales are recorded. Product packages, prices, and promotions change all the time and while it may be easy to keep track of sales, units sold, etc., the actual storage of this information is much more complex. Retailers need to structure their data in a way that allows analysts to determine how the sales were generated. In addition to knowing Coca-Cola had an increase in sales last month, innovation on packing, price, and promotions lead to technical requirements to know which specific UPC of Coca-Cola, at what specific price point, under what promotion, and at what location in the store drove those sales.
As for packing, price, and promotions, it does have a bearing on how inventory and sales are recorded. Product packages, prices, and promotions change all the time and while it may be easy to keep track of sales, units sold, etc., the actual storage of this information is much more complex. Retailers need to structure their data in a way that allows analysts to determine how the sales were generated. In addition to knowing Coca-Cola had an increase in sales last month, innovation on packing, price, and promotions lead to technical requirements to know which specific UPC of Coca-Cola, at what specific price point, under what promotion, and at what location in the store drove those sales.