I know that I saw this youtube video once (probably one of those old google tech talks), where they presented their system for maintaining a production system with strict modular version control in a monorepo, complete with how the migrate between major/breaking versions and navigate dependency hell. I think I kind of disregarded it because it centered around a somewhat-uncommon programming language (Elm?), but I think of it every time I see half-baked version systems (that is, every day) and I can't find it because search sucks and any notes I took on it were not indexed.