If a microservice architecture needs a separate database per microservice then it's too costly & unmanageable. Why do we even need it?
I read about microservices and it seems illogical to me to create a separate DB per service just to achieve isolation. I can achieve the same using only web services and a single database. Why do we even need it? The thing that separate database is beyond discussion. Or I am plain wrong? Can you guide me on this?

I read about microservices and it seems illogical to me to create a separate DB per service just to achieve isolation. I can achieve the same using only web services and a single database. Why do we even need it? The thing that separate database is beyond discussion. Or I am plain wrong? Can you guide me on this?