For an internal-only dependency it's possible. But if you've got a lot of active branches, or long-lived feature branches, it'll create chaos in merge conflicts. Even worse if you've got multiple supported versions of a product on release branches (e.g., `main-v1.0`, `main-v1.1`, `main-v1.2`, and `main` itself for the yet-to-be-released `v1.3`) you either make backports awful (by only changing the import path on `main`) or have to change even more things (by changing the import path on the release branches too).

It's effectively impossible for pubic-facing dependencies. Imagine if https://github.com/sirupsen/logrus wanted to change their Go modules import path, for example to move to another git hosting provider. (Logrus is great by the way, I'm only 'picking' on it as a popular Go library that's used everywhere.) GitHub tells me that almost 200,000 Go projects depend on it (https://github.com/sirupsen/logrus/network/dependents), so all of them would need to change every source file they do logging in (probably most of them) in order to handle that.

GitHub seems like it's going to be eternal for now, but when the industry moves on in 10 years time every single Go project is going to break. This would be a problem for any source dependency management solution of course, it's not like any of the others are immune to this issue. But because Go has you encode the Git path in every source file you import it into, the level of change to fix it is an order of magnitude higher.