The better question is "Why fire Jim Zorn now?". Not to be a jerk, but I don't see any advantage to the team gained by firing him now. It's not like they are going to make the playoffs and no one expects anything from them at this point anyway. Why pay someone a boat-load of cash to be a pseudo head coach for two games and possibly just confuse things even more than they already are? If they bring in a new "head coach", who's going to call plays? Same guy they already have calling plays. So what's the new guy going to do other than NOT call another "swinging gate" formation play (which I have a feeling won't get called again anyway

).
Zorn is not a good head coach,
but the players do seem to still be playing for him, which is about as much as could possibly be expected from the team in the current circumstances.
The guy I feel bad for is Campbell. I'm a Steeler fan, but I live in DC and have become a Campbell fan. You can say he sucks and I won't argue with you, but I will say that it is exceptionally hard to evaluate a guy in a chaotic situation like he's in. From what I've seen and heard he's a very hard worker, an excellent citizen, etc. Management has dumped all over him, he's taken a pounding all year, some of his team-mates are VERY me-first type players, and you NEVER hear a negative word from the guy. Last night for example he's getting blasted physically and blasted from the stands for an entire half. But in the second half in an obviously already lost game, instead of mailing it in, he's out there scrambling to make first downs.
And now he's in a "contract year" and his team is crumbling around him despite his best efforts every week. I know he's been in the league for a while and a guy will generally show what he's capable of by this point in his career, but I hope some team out there will give him one last chance to show something because he's really a guy you can root for.