We need to look at the role more broadly, being a developer isn't just churning out code. A lot of young talented guys just follow their passion and hack away a

We need to look at the role more broadly, being a developer isn't just churning out code. A lot of young talented guys just follow their passion and hack away abstraction after abstraction instead of trying to see what the product really needs. So you could say they're amazingly productive, or you could say they actually provided very little value. And a toxic wreck can't be productive by definition; if you demoralise everyone around you reduce productivity! The fact some people can get away with is a bug in hiring.