Re: I finally watched Firefly! (SPOILERS)
I think Indyjones is correct though. Whedon had abandoned any TV revival when he wrote the film screenplay.
Well, yeah, he abandoned any attempts to revive it on TV because it was just never gonna happen. But that doesn't mean that there was some sort of legal barrier.
"Every line of serious work that I have written since 1936 has been written, directly or indirectly, against totalitarianism and for democratic Socialism, as I understand it." - George Orwell, 1946