This misses two big aspects of software engineering as a whole; the more code you already have the, the longer it takes to add new features, and the more people

This misses two big aspects of software engineering as a whole; the more code you already have the, the longer it takes to add new features, and the more people working on a code base, the long it takes to coordinate. These two aspects mean you need more and more people to move things along. You multiply this with that doing a service in multiple countries is more complex than one.