This. I should have added context that my experience was in small companies where it wasn't really possible to change teams. But some of the people that were bad performers became good performers only after they were fired and found new jobs. I've seen this happen at more than one company. They were probably just demotivated or hated their boss or something, and no amount of intervention can really fix that, short of a change in job (or a change in team, as you mention, if it's a bigger company).