I used to think this way as well. Then I rebuilt the performance management system at Accenture using domain centric micro services and a document database. Not only were we able to build faster (schemaless is so much easier on change management), but also offers the ability to add features at a frighteningly fast pace. No RDBMS-centric project I have ever worked on comes close to the efficiencies of what we did on that project and on projects since using the same paradigms.

And when people needed the transactional data in a relational model, we streamed events and that was read only in some other tool and the core system didn't need to know about any of that.

Been down this road. Saw a fork in 2015 and haven't looked back.