That would imply that they're able to correctly identify their "weakest performers" with sufficient accuracy to do that. From what I've seen of large corp. per

That would imply that they're able to correctly identify their "weakest performers" with sufficient accuracy to do that. From what I've seen of large corp. performance appraisal systems, that's very rarely the case. Those systems tend to reward people who are good at self-promotion, not necessarily people who are good at their jobs.