Hmm, that said, this could easily just be a reflection of biases and preconceptions software engineers have about Walmart. For all you or I know, those guys over at Walmart Labs/Walmart Ecommerce are having a blast and getting paid a bunch to do it.
I know a few people here who say that it is their "dream" job. But, that's mostly because @WalmartLabs is treated like an independent startup with its own management, ecosystem, and philosophies. The employees who can make a huge impact and have awesome bosses are very happy - this would be true at any company.