Comment by Closi

You've not really built microservices then in the purest sense though - i.e. all the microservices aren't independently deployable components.

I'm not saying what you are proposing isn't a perfectly valid architectural approach - it's just usually considered an anti-pattern with microservices (because if all the services depend on a single monolith, and a change to a microservice functionality also mandates a change to the shared monolith which then can impact/break the other services, we have lost the 'independence' benefit that microservices supposedly gives us where changes to one microservice does not impact another).

Monoliths can still have layers to support business logic that are seperate to the database anyway.