With the hindsight of 20 years in the industry I believe a lot of it is due to team churn. Once the original developers are all gone much of the codebase become

With the hindsight of 20 years in the industry I believe a lot of it is due to team churn. Once the original developers are all gone much of the codebase becomes a scary black box. When I think about teams I've worked on with an OG dev still around, they've always been far more productive.