To the point in your last sentence, a few years ago I worked at a software company where there was a prolific code writer who similarly tied up about ~2 SWEs cleaning up his messes. He was a Perl programmer who was set loose on C# code. The broken ways the company tracked productivity meant the prolific writer rated as doing great while the three SWEs who had to spend 2/3rds of their time fixing the messes he left behind were rated as unproductive.