That's what the basic wage is for. They're not being paid to stand around.
Tipping is for the "above and beyond" service.
-PJ
I don't know what restaurants YOU go to, but servers that I am familiar with don't just stand around. In this area, servers are run ragged. It is nothing for one server to have 4 to 8 tables to take care of at all times. High end establishments may have a better server to client ratio.