In my career as an operations manager and project manager, I managed and interfaced with “production DBAs” and “development DBAs”. My operations and infrastructure teams had “production” DBAs. They had ownership of the databases, tuned and optimized procedures and queries and provided architecture advice to peer development DBAs and developers. They did not have responsibility for developing business logic. They deployed code and had exclusive access to Production data. This fulfilled the division of labor requirements of good best practices, as well as ITIL, CMMM, and various security/compliance frameworks.
I suspect those in smaller shops may challenge this logic, but it seems to be the standard in enterprises, disciplined IT departments, and shops subject to compliance. Here are some supporting opinions.