ETA: Re Rome, which I loved, that was on cable and they have more money, plus they spent a shitload of money on sets, which - in the end - I guess never managed to amortize fully, seeing as it didn't last beyond a 2nd season. That said, I can't see a network show spending more than 4 mill per ep (for a drama) to recoup its money.
The thing about Rome is I think it was worth its price, I caught a few epsiodes and it looked like a fantastic tv series