Replying to
@david_chisnall@infosec.exchange I think though, it makes sense for them: in a large enough internal repository generated by thousands of engineers, you'll likely find a problem/solution near enough to yours, and reusing/adapting instead further proliferating has theoretic maintainance value.
Not saying this is what actually happens (often it is genuinely easier to roll your own than adapt/share something existing).
Then there are always the problems or people you can't contain, generating enough novelty.