Firstly, employee-related shrinkage includes inventory control and accounting errors ("paper shrink") in addition to employee theft. These are often added together to differentiate them from external theft, but they're not the same and the mitigations for each are as different from each other as they are from external theft.
Second, and relevant to the GPs point, there is variation in the amount and proportions of shrink from one site to another across a chain. The stores that get closed are the outliers, not the average stores. e.g. Your chain wide average shrink is 2%, but all of your stores in this one market are 10% for several years running. Realistically, the difference is almost entirely from external theft.
Laundry detergent is actually a really common item for resale, maybe because everyone uses it. You will see people with 40 gallons in their cart and you know they aren't paying.
Its not a fun experience.
Overall my point is just that the retail theft story is blown way out of proportion, and many media and political outfits benefit from concern around crime.
I think the more interesting questions are if the rates of theft are changing. IF it has gone 10x in 10 years, that might be noteworthy, no? If theft rates are concentrated in 10% of locations, that might be noteworthy too.
My national retail supermarket has profit margin of about 1% of sales (ticker ACI). If mismanagement was always 1%, and now theft goes up to 1%, the company will go bankrupt.