Other shows scoring low ratings won't help Fringe get a renewal this season. Its chances for renewal are entirely dependent on how it does on Friday nights. If by some slim chance it can keep its ratings erosion when it moves to Fridays to a reasonable level then it'll be back for a fourth season, but with Fox's development slate for 2011/2012 there's no way it's going to get one of the coveted time slots and its ratings have eroded too much to be kept in its current time slot. If Human Target, Lie to Me, and The Chicago Code all tank in the ratings it won't save Fringe if its ratings are likewise poor. Fox will simply cancel all of them. It has enough product in the pipeline for 2011/2012 to do so.
I don't agree wit that. If every show on Fox has worse ratings then it will make it look like Fox has a problem keeping viewers and not just Fringe.
Which in reality is really part of the problem. TVbythenumbers.com had an article talking about what shows improved the most in the demo this year (I think number one improvement went to Modern family). They also broke it down to network and Fox's demo numbers have dropped 20% this year.
Plus Fox show have canceled Fringe, Human Target and Lie to Me last season, they had plenty of shows to kill in the holes and they didn't. Even with Fox having no room for any shows they will still keep some extras just in case of failure.