I've worked in two major microservices environments. The one was a new application where everything was sloppily wired together via REST APIs and the code itself was written in Scala. A massively weird conflict there where the devs wanted a challenge on a code level but nobody wanted to think about the bigger picture.

The other was an attempted rebuild of an existing .NET application to a Java microservices / service bus system. I think there was no reason for a rebuild and a thorough cleanup would have worked. If that one did not move to the microservices system, the people calling the shots would not have a leg to stand on because the new system would not be significantly better, and it would take years to reach feature and integration parity.