I've seen plenty of bosses who will try to improve someone even if they know they are leaving in a couple years, telling people to make sure to get on LinkedIn

I've seen plenty of bosses who will try to improve someone even if they know they are leaving in a couple years, telling people to make sure to get on LinkedIn so they can rate them up, etc.. There's much less loyalty to companies nowadays, but people do have loyalty to their superior if the superior is setting them up for success no matter what. So I think a good boss does have some traction on a person's career, not just their advancement in a single organization. Companies and management that push to make their employees better overall and not just for themselves often brag about it too.