I worked in a supermarket in the early 80’s.
One of the main attractions of that job to me was the large number of female cashiers 18-23 who were working there.
I think we had 15 registers. At least 12 were nearly always open. Pretty much they all had baggers, and there were guys out stocking the shelves as well.
I was in that same store two months ago, and counted nine employees in the whole building, including the manager.
It’s been something of a joke here for almost as long as I can remember, as to just why grocery stores put in so many checkout lines but never fully staff them. We get a rush on the grocery stores ahead of storms, hurricane, ice, snow. They’re not even fully staffed then. Lines to the back of the store for the ones that are open, but still empty closed lines with unstaffed registers.