Yes, you have to handle the failure case of "network call". Microservices add this failure case. But you already had to handle the case of "code blew up because of a bug".

By forcing you to handle comm errors like network failure, you also force people, implicitly, to handle "code blew up because of a bug" errors. Even though it adds a second error case, you pretty much handle them the same way in the same place.

There was always an error case - the fact that code may blow up.