You can always change the source of truth so instead of being the JSON texts it's the properly normalized schema and then you can have a VIEW that returns JSON

You can always change the source of truth so instead of being the JSON texts it's the properly normalized schema and then you can have a VIEW that returns JSON for apps that need JSON. And if need be you can denormalize a bit and have a JSONB column that stores the document as the serialization of the rows' other columns. That's what's really nice about SQL: you can perform these sorts of schema surgeries and still retain backwards-compatibility using VIEWs.