The stuff on their shelves is less valuable. They also get more traffic and seem to have more security cameras and staff. Target has had a lot of thefts. If I'm not mistaken, Target had an AI system to track faces of shoplifters and the accumulated value of the stuff that was stolen. Costco won't generally let you in if you don't have a membership, and there are people at the entrances and exits at all times.

Have you not seen the stores like Walgreens that have very basic toiletries behind glass? This stuff is very location dependent and some cities (most?) are still normal. Many stores including Target and Walmart are using AI to track shoplifters. They have had to resort to adding up thefts over time until it totals over $1000 or something, because theft is so pervasive. That's not the kind of theft you need outside cameras for, but these stores see it all.