It's entirely possible (and this is pure speculation) that this was a pattern his managers observed, and one that continued even with regular corrective feedbac

It's entirely possible (and this is pure speculation) that this was a pattern his managers observed, and one that continued even with regular corrective feedback. I've been on the managerial end of that situation and it's really no fun when no improvement is seen even when expectations (and consequences) are clearly and explicitly laid out. Some people just don't get it - but again totally speculation, may not really apply in this situation.