[adsfasge]

You seem to use these terms interchangeably - people who do the absolute bare minimum, mediocre-ly poor but not egregiously bad performers and sub-par, while I think they are all different.

Every employee is either sub-par, at-par or above-par. If you perform the minimum to not get fired, you are necessarily doing what's expected of you, you're at-par (maybe you wont get promoted but you are doing what's expected of you), and if you are doing more than you need to then you are exceeding expectations.

This thinking that you can do what needs to be done to not get fired, but still be under performing just tells me its a bad manager(s) with no clear expectation setting and communicating it and if anyone is clearly sub-par making sure its communicated early with clear expectations instead of a doing a mass layoff to try and hope fix it.