I suppose that the long lines go next to aisles with some last-minute stuff like candy, chewing gum, small toys, etc, which the bored people in the line have to see and may feel a craving to grab. If not them, then their children who experience boredom more acutely.

no, it's just a burned out lightbulb.

I believe it, but what were they trying to optimize?

If all of their changes are focused on near-term bottom line, is it really surprising if that comes at the expense of customer/employee satisfaction and brand reputation?

Walmart ultimately measures everything against lifetime customer value. They don't really care about maximizing revenue on a specific trip because most people come in to the store with a fixed budget of what they can spend anyway - but they sure as heck want you to return.

Fixed income customers see things like an ultra clean speed and efficient store as 1) intimidating and 2) overhead that makes prices go up and "wastes" their money.

I’ve seen Walmarts churning through shoppers with really impressive speed so I guess some of them didn’t get the memo.