Not while they’re under contract they don’t. When you sign a contract indicating you will submit X number of episodes per season for Y number of seasons then that’s what you have to do. There’s only two ways out of that kind of contract: complete it, have the network void it by canceling your show. And option 2 only exists because that’s built into these contracts. And even after you complete it you don’t generally have the freedom to take the show elsewhere, the networks excercise a high level of post airing ownership of shows (which is what allows them to show reruns and sell to sindication) that makes it so if the producers leave they’ll have to start a new show from scratch. If M&T ever leave CC it won’t be to take their popular show to another network, it’ll be to try to make another popular show on another network, unless they’ve built the sexiest contract in TV history.
I don’t think they were necessarily brave to slam the network, but it was more of a demonstration of spine than you generally see in these kind of conflicts. In general when a network says know producers take one of two options: they try to negotiate or they fold outright. M&T made the episodes the way they wanted and put the ball in CC’s court. And given when CC told them know that was some spine, CC could have easily refused to air the episodes and refused to count them against the contract. That would have probably led to a court battle but CC probably would have won, generally speaking if the network says know to an episode before it’s even scripted they win that fight.