On a large project you will have problems. You can maintain a monorepo anyway as many people do, and deal with the problems of a large monorepo. Or you can go to multirepo and deal with the issues of multirepo. Both have been done successfully, and both have significant problems that you need to work with.
Most people advocating a monorepo have never worked on a project large enough to see the issues with a monorepo and so are arguing for a monorepo without understanding the problems with them. For most people a monorepo is the correct answer because their project is small.
Most people advocating a monorepo have never worked on a project large enough to see the issues with a monorepo and so are arguing for a monorepo without understanding the problems with them. For most people a monorepo is the correct answer because their project is small.