DBAs are supposed to bring knowledge of the underpinnings of databases to the table. How to lay out tables and indices across disks for linear vs. striped access. How to properly set up partitioning for different types of access. Granting assorted privileges and roles. Managing backup and aging off data in a controlled manner, and so forth.
A long, long time ago, in a phone company long since gone and resurrected, if Aunt Bee wanted to call Sheriff Andy, she picked up the phone, pressed the receiver a couple of times, the operator picked up, Bee said to connect her to Andy, and the operator shoved a jack into a hole to complete the circuit. For long distance calls, two or more operators and switchboards were involved. It left something to be desired, but it worked.