Even if your modules are very separated, if you can't individually use and play around with them they become a part of a big blob of software. Services may be products, but only if they're idependently usable.

If you have a small product that's useful in and of itself (e.g. git) you can much more easily make it work well and then integrate with other good tools and replace those if necessary (e.g. if you have problems with Bitbucket/Jira/Confluence, you can switch them out for other solutions, e.g. Gitea).

But if you have a huge clomplex product then at some point it becomes organizationally impossible to move away from it.