[barryhunter]

Why does there need to be a business case?

Its quite probable the engineer that built the layer has left (either Google altogether, or just to another team).

As its aged its started misbehaving, and nobody left is interested enough to figure how to fix it. Ultimately its easier just to ditch it than to maintain.

euthanasia rather than murder.

[tomrod]

Sounds like a good case to ensure documenting of codebase is expected. Is bitrot a normal thing in firms such that somewhat large projects are abandoned because of poorly documented code?