Let's say you started with a well factored set of code that is managed within your organization. What advantage is there to having multiple repos if you're not limited by your tools? Refactoring is easier within a single repo...
In my experience, code doesn't stay well factored unless there are technical hurdles that keep it so. That of course doesn't have to be a repo boundary, but in can be.
There probably will be a plethora of different hard issues to fix in such situations.
It's also easier to institute change in a dictatorship as opposed to a democracy (being a dictator that is :).