difficult question. I guess... it depends?

Some manage well more than just the database.

Here, we fix anything that is down, broken or acting up. Work on performance tuning when we have time or if a need arises. Build up new systems and help address coding issues. Maintain SA functions and repair any other issues that show up short of the actual OS or server (we still have SA's for this as well). Work oncall issues 24X7. Support any version or option that is installed with SQL. Attend meetings and conference calls to help with the design of new systems. Keep customers happy. Drink coffee and eat pringles. I'm sure there's much more that's being missed.