smaller number of SKUs and not consistent. you can find something on a visit, and then it is not available on a subsequent visit. but i now know this going in, and still benefit from the items that are available

It's intentional. See https://customerservice.costco.com/app/answers/detail/a_id/7...

The idea is that if you see something that interests you, you buy it now, and there's always something new on each visit. It's annoying for certain things, but at the same time it allows them to avoid having the same stock on the floor because people are on the fence about a purchase.