Former agent Gavin Polone (he was one of the main ones representing Conan O'Brien during the Tonight Show debacle) explains about packaging fees in Hollywood. Packaging fees are one of those things that everyone complains about but no one does anything about. I was involved in a couple of projects that went unsold because though a network wanted them, there was someone else involved in the project who was represented by an agency that was demanding a substantial packaging fee…and the network was not willing to pay that much.
It's a reason some shows don't sell and why others get canceled. But like I said, no one does anything about it.