Why do advertising agencies neglect search marketing?

One could argue that the most effective medium for marketers today is search engines. Yet almost no advertising agencies have search marketing as part of their core competency. Why is that?

Our firm has taken a very different path and invested in building a strong search marketing team. We are one of the few full-service agencies to be recognized as Google AdWords Qualified. This not only allows us to provide much more unbiased media recommendations to clients, but allows us to do very efficient message and offer testing with quick PPC programs that can then be incorporated into other media activities.

So I’ll ask you, can an agency truly be “media agnostic” without incorporating search in its media planning portfolio?