He describes his reasons for doing so in Ad Age’s Small Agency Diary. I like what he says about returning to someone else’s agency after running his own.
Funny thing the perspective you bring back into an agency after running one. You’re like a kid in a sandbox again. Your knees stick out of the sandbox, because you’ve grown. You can see what everyone’s doing because you’re just a little taller. You understand the cost and construction of the box better than most. And you know exactly what makes the sand so much fun! You can even listen to others tell you something you learned years ago and be excited about the new way it’s being expressed. But the best part is rolling up your sleeves and remembering you haven’t forgotten how to play.
I know when I returned to The Integer Group after a year of freelancing, I had a totally renewed view of the place and my role in it. Of course, it didn’t last, but at first, it was a real high. So, I can relate to what Brimm’s saying.