> Do you have a source for that?
I know people who work there.
Your average Walmart has hundreds of camera housings. Every single aisle has a couple. The amount of cabling alone to populate them all simply doesn't exist (as you can often see, it is an open-box ceiling), and monitoring that many cameras is impractical (in particular for a store staffed at BARELY sustainable levels).
Just look at how understaffed the floor of these stores are, then ask yourself why they'd have a disproportionate number of loss-prevention staff working relative to the floor staff. A big store absolutely will have tens of cameras, but even all those may only have a single person for all (or zero persons depending on shifts/staffing).
That being said: Some stores have legitimately rolled out facial recognition to pick up known thieves as they enter the store. But that requires four-ish cameras and the technology is pretty turn-key.