Having worked at a Target like this, I can assure you there is still a lack of inventory on top of these stores being extremely short staffed. Target in particular completely eliminated their storeroom staff a few years ago and just doubled the work load of the floor staff. Both the floor and the storeroom were absolute nightmares to navigate because there were not enough people to actually organize and stock.
Saying an ISA is just a hardware API vastly oversimplifies what an architecture is. There is way more to it than just the instruction set, because you can’t have an instruction set without also defining the numbers and types of registers, the mapping of memory and how the CPU interacts with it, the input/output model for the system, and a bunch of other features like virtual memory, addressing modes etc. Just to give an idea, the ARM reference is 850 pages long.