1. It angers people enough to commit murder if they see someone who arrived later served earlier.
2. The serpentine line format (one line forms and the first person goes to the next available register) is more pleasant psychologically than separate lines for separate registers because it is first-come-first-served.
3. Therefore, supermarkets must be "lagging behind" or missing opportunities to serve customers.
If you're missing opportunities, you're missing money.
The argument has appeal. After all, you remember especially long wait times. And, the next time you choose the grocery store for the week, you might switch to avoid a long line. Given this reasoning, long lines drive customers away. If the grocery store would rather keep customers, what gives? Why do grocery stores stick with the anger-inducing separate-lines-for-separate-registers system? Can grocery store managers really be that stupid?
These are all good questions, but they're based on an implicit assumption: The grocery store's goal is to minimize queuing time (or minimize bad feelings from queuing). Under this assumption, we get a radical solution like this:
Dilip Soman: I have a radical solution. Once a shopper is ready to check out, she wheels her cart into an area where she gets a number, and is directed to a lounge. Staff members scan and generate ‘invoices’ and once ready, the numbers are called out into the lounge area so that the customer can pay. The one thing that I don’t know is whether customers will feel some anxiety about not being in front of their groceries when they are being scanned, but if they don’t, I think this will be the most efficient solution! (Jeff Ely's favorite solution, given in the text of the article)
I agree that the solution would be best for the consumer (who wouldn't love to kick back in a lounge while everything is handled?). But, in the spirit of the article, you've got to ask why the "Supermarkets Haven't Caught On." The article presumes is that it is obvious to provide such a lounge, or any other consumer-welfare enhancing change to the current system. In other words, the article presumes that grocery stores maximize consumer happiness.
That's not what we learned in introductory economics. In Econ101, we learned that it's useful to assume grocery stores maximize their own profit (just like any firm does). Profit maximization may or may not lead to observably-happy consumers. For that matter, a grocery store that is good at obtaining profits may deliberately increase the length of the line.
Why? Think about your experience when you're waiting in line at the supermarket checkout. You see magazines, piles of candy bars, breath mints, the extreme value buy, etc. At a Jewel-Osco I frequent, they've even started installing miniature TVs that continuously play advertisements.
Maybe you have a weakness for Kit-Kats; Maybe, People gets you excited. Regardless, it looks like the grocery store uses your queuing time to reach into your wallet one last time. They use it for inducing impulse buys.
Moreover, it's in their interest that you wait some amount of time. After all, you get maximum exposure to the in-line advertising if you have to wait. Otherwise, you're just busy paying for the products in your grocery cart. I have a feeling that the supermarket wouldn't mind if you added to your cart.