Isn't this generally because they didn't fire low performers one by one, but instead those people just build up and get laid off all together? It's a terrible pattern (firing known-bad staff is good for morale, layoffs are bad for morale) but extremely common.
As much as people hate stack ranking and enforced "unregretted attrition" at places like AWS, it seems like the only way to ensure managers actually fire deadweight.
The bigger problem was deadwood employees, but deadwood projects and middle-managers who built out their fiefdoms. The smarter approach would have been to do a better job moving around the best employees in more comprehensive reorg. But that is very difficult to execute well.
This always seems to be a worse problem than IC performance. Managers have power to remove ICs. But nobody really has a lot of power against politically strong dead weight projects.
Fun story. I worked with a guy who had a habit of killing any project he was on. Guy was fantastic at certain feel good maneuvers that had a tendency to suck all forward momentum and enthusiasm. He was a nice guy, and it was clear he had positive intent.
I would unequivocally hire this guy if I was a C-suite and place him on any project I couldn’t kill but wanted to stall out.
As much as people hate stack ranking and enforced "unregretted attrition" at places like AWS, it seems like the only way to ensure managers actually fire deadweight.