As much as we want to pretend that slowness correlates with attention to detail and quality of code, this is often only rationalization. Some people are perfectionists (in a bad way) and overcomplicate things that don't really matter to the end result, others have analysis paralysis and take too long to make decisions, making the code suffer, and others are just not that great and generate the same result as a faster developer at best. There are surely good but slow developers, but it's not as common as "internet common sense" paints it.
And disavowing their role in cause and effect. They play chicken with other developers, who end I sacrificing their own productivity to fix the issues. Bad managers see this productivity gap and reward the hack instead of punishing him.
