For a show that makes it past 3 seasons, the issue becomes dealing with the increase in salaries for the top production personel and cast. If those inflate the costs beyond what the network's license fee is, or what the studio is willing to cover, then the show can be ended regardless of how much better it's ratings are in comparison to others on the network. Not helping here, is that both the studio and network are basically the same- Universal Cable Productions is the studio and it's under the aegis of NBC/Universal's cable division. The studio may not be motivated to cover additional costs incurred by wage increases, or by a reduced license fee if both are corporate siblings...
Warner Bros, in order to gain a fouth season of Fringe, covered the reduced license fee Fox paid, in exchange for keeping the show on for one last year.
Dazed and confused over high tech.
Sigh...Concrap. The Internet Overlord Cometh
They're not com-tastic!