The most efficient solution for advertising agencies to adapt to a changing macro environment has always been to remodel and reinvent itself. But is this survival strategy the best one today when communication trends have a lifespan of 12 months? I'm not sure. Reinventing an advertising agency takes lots of time, and time is money.
I don't have the solution, but I'm not sure the future of the advertising agency lies in capitalising on specific expertise/resources to gain short-run competitive advantages. Rather, it may lie in the capability to deliver creative thinking over the long-term.
At an extreme this would mean that the things we call planning tools are pretty useless for getting ahead (not per se, tools are still good for efficiency). Instead of being focussed on WHAT ideal are going to achieve, planning would in this alternative reality be focussed on HOW we will achieve our ideals.
Just a thought.
Footnote: planning guru Russell Davies wrote a piece on The Planning Lab about the greatest planning challenge not being brands but organisations here.