I wasn't directly impacted by this, but from the few instances I've seen, the people being ousted seem to be those that had questioned tech. decisions. They were people who did badly during our review process.

For instance we have a brand new react server side rendering based platform. I think the performance of that framework is somewhere around 2 concurrent requests per virtual machine. And we're bragging about our performance chops publicly: https://medium.com/walmartlabs/using-electrode-to-improve-re...

Wal-Mart has many problems, I don't think too many experienced engineers is one of them.