You actually have to do versioning property, though. Most people I've worked with do not understand semantic versioning and basically don't understand how to ship new features in a non-breaking way. That or they're too lazy to do it. Either way, dependencies get broken constantly.

That's the real point of a monorepo: you can treat the whole thing as internal, break it to your heart's content. You only need to make sure you don't break the user-facing part, for some subjective value of break.