You are entirely right, but permit me to respectfully add a few points I think are critical. First, the two domains of knowledge are not mutually exclusive. A

You are entirely right, but permit me to respectfully add a few points I think are critical. First, the two domains of knowledge are not mutually exclusive. Almost all SQL experts/DBAs are also able to do many forms of more conventional programming, and do them properly. Similarly, many software developers know SQL reasonably well and can write good set based code when they choose too. Second, if working in the other domain, you pay a hefty price for not approaching that domain on its own terms. Using loops and cursors in MS SQL Server is enormously less efficient than the same solution done in sets (Oracle has a slightly narrower gap, but still a gap. I suspect the same is true of all RDBMS but I can only speak to those from experience). On the flip side, if a normal database developer is shoe horning data into an RDBMS that is not relational, that will cause complications as well.