This article misses a very big reason. It's a scheduling type problem. They rarely have good systems in place to deal with taking bad trollies out of service, so they stay in service and sit at the front of the stack, because some people notice and reject the trolley but they generally find their way back onto the stack. If you always take the first trolley of the stack and regularly find it is busted it is probably…
FIFO is more likely to keep pushing the bad one to the front, whereas lifo will eventually have the far carts be the bad ones.
But I’ve rarely if ever had a bad cart so maybe this is an issue somewhere else. It is amazing to realize that at about $200-400 a pop, the average Walmart has something like a quarter million dollars worth of carts.