Large corporations assign people roles. The person watching the cameras is there to detect shoplifting. They have no stake in the success of the store.
If you want to see a shopkeeper care about that sort of thing, patronize an owner-operated small business.
I don't know about small, but the store I usually shop at is owner-operated (though part of a owner-coop in Germany), but they don't do it.
I get the point of shoplifting watchers not caring about queues, but am I just naive that this should be easy enough to solve with tech? You have lots of images from multiple directions, you know how the store looks empty, you can probably do a decent-enough image discovery to find out roughly where people are. If there are 15 people in front of the checkout, ring a small bell somewhere and have a person check whether it's time to open another checkout.
I can shop, scan the products while I walk through the shop with my phone, pay with the app and open a gate to bet let out with my purchased goods, but the computer can't use the camera signal to figure out how where people are?
The tech is redundant. The people working in the store can see with their eyes how long the queue is. They don't need a machine to ring a bell. They have a brain.
If you want to see a shopkeeper care about that sort of thing, patronize an owner-operated small business.