The article isn't related to repo structure, however repo structure can relate to the core issue of how to share code and maintain domain boundaries - search for the "umbrella" thread elsewhere in these comments.
Just because repo structure can relate doesn’t mean that such a relationship involves any properties of monorepo structure vs polyrepo structure.
Any messy code organization or dependency issue you can have in a monorepo, you can also have in polyrepos. Any automation or central controllership you can have in a monorepo, you can also have in polyrepos. Any scale-out chores or overhead work you can have with polyrepos, you can also have with monorepo.
The issues of monolith / poorly coupled dependency applications vs microservices has absolutely nothing to do with monorepo vs polyrepos. Neither option makes any class of tooling easier / harder to build or maintain. Neither makes conceptual organization easier / harder to get right, neither makes discoverability or cross-referencing easier or harder. That whole axis of concern is just fundamentally unrelated to the application monolith vs microservices question.
