[makoz]

I guess to some extent it's about some aspect notion of "fairness". Another concern would be if their poor performance spills over into my own role and that prevents me from pursuing more interesting tasks that are more aligned with my growth/interests.

More practically, if I'm working at a place where my team has fixed head count I'd rather us have the ability to replace someone who's not contributing to the success of the team.

[notabee]

This can definitely be a burden, though on the flip side of the coin if the team is constantly churning due to cooking under a performance magnifying glass all the time, you still end up with lots of newbies who only just get up to speed enough to contribute for a bit before moving on because it's miserable. So sometimes it's better to deal with the problem you know, and just move them out of the critical path.