This article conflates the Monolith|Microservices and Monorepo|Polyrepo dichotomies. Although it is typical to choose Microservices and Polyrepo together or Monolith with Monorepo, it's not strictly necessary and the two architectural decisions come with different tradeoffs.
For example you may be forced to split out some components into separate services because they require a different technology stack to the monolith, but that doesn't strictly require a separate source code repository.
For example you may be forced to split out some components into separate services because they require a different technology stack to the monolith, but that doesn't strictly require a separate source code repository.