Why is it that digital people who have been extremely successful at pureplay, smaller digital shops seem to struggle in driving change at big agencies?

So again, the cycle is head of innovation person gets the agency stoked up for a piece of work, it launches (having cost the agency a fortune), people talk about it, but it does nothing for the client and is terrible for the bottom line of the agency. It’s a false way of working. The digital shops have no need to play that game so people can concentrate on doing good work.

Confessions of a Big-Agency Top Digital Exec | Digiday

Well this is damning.