[jacobvosmaer]

I think the issue is about having to cross a module boundary, which is really about monorepo vs multirepo. You have much more freedom to make breaking changes when you don't need to cross a (repo/module) boundary.

I think the Go module system encourages you to avoid adding unnecessary boundaries. As someone else pointed out already, one of the problems is that you don't find out that boundaries are bad until you hit v2, and then you discover that you have this chunk of technical debt (unnecessary repo boundaries that slow down development) that you didn't know about.