I don't quite agree with Kevin Carey that the cancellation of Dollhouse makes Joss Whedon a greater tragic figure in the annals of popular culture. Doing another series with Fox after they wrecked Firefly was completely inexplicable, except out of friendship with Eliza Dushku and relief that he'd gotten a plausible new idea for a show, and I don't buy Matt Yglesias's argument that it was all about money. I find it highly unlikely running a series on Fox that you know is not going to be supported and will be canceled in two years at the outside is more profitable than a deal for a cable series that will actually be successful over a longer period of time, albeit at a smaller scale.
To me, Dollhouse is just a further expression of the catastrophe that was the cancellation of Firefly. Even someone like Joss Whedon doesn't have an infinite number of great show ideas. Gene Roddenberry didn't have a great idea to follow up Star Trek, for example. Even David Milch drops stinkers like John from Cinncinnati. The reason Whedon so doggedly stuck with Buffy and Firefly, to the point of doing movie and TV versions of both, is that he knows ideas that good only come around a few times in a lifetime.
OTOH, maybe he knew Dollhouse was a good, but not epochally great concept, so why not use it on Fox? It is no great loss.