Putting it All Together

What is the role of the instructional designer? Are instructional designers cogs who merrily work with content or do instructional designers need to do more? In today's world it seems that an instructional designer should develop an additional set of skills, namely either some type of programing or graphic art. But then what is really happening is that one person takes on the role of two or maybe three people. A really good graphic artist is not simutaneously figuring out calculus while creating art. So why is it that in the field of instructional technology companies expect an instructional designer to do it all? I do not know. Makes me scratch my head but that seems to be the way.