A single line to 3 cashiers is ~3x faster than a separate line for each cashier
What I didn't see in this article is why retailers don't do this today.  I see a lot of positives listed and no negatives, so it seems like a no-brainer, right?  Yet the biggest retailers like Walmart and Target have tons of lanes, and even do staggered front/back lanes which are terrible for the customers.  Is it because there are negative feelings to seeing a long line, and that people do not expect it to be fast so they abandon their purchase?