It sucks, but isn't entirely surprising. I fully blame the writers, who put out a string of about 6 episodes that sucked badly, and killed all of the show's momentum and casual fanbase. I cannot fault Fox for not supporting this show. They plastered the airwaves with advertisements, tied in the adverts with NFL games, etc, etc, etc. Fox could have canceled the show half-way thru the season quite easily. Instead, they granted the show a 2nd half pickup to finish the season.
The Friday move did kill the show, but Fox didn't really have a choice. It was really the only night of the week it could face weaker competition from the other networks. A friend of mine told me he didn't get to watch the last string of good eps due to this move.
Dollhouse was renewed, for a very interesting and unusual reason - the mysterious and unaired 13th episode. They were contractually obligated to make 13 episodes, so Joss Whedon and co. just whipped one together knowing in advance it would not air. They then used this episode as a proof of concept that they could make the show on the cheap.
Terminator went out on a high note, but it was an expensive and production heavy high note. Setting season 3 in a futuristic (expensive production) setting didn't help Terminator's cause.