On the wider issue here I do wonder if there's something to Andrew's observation about the existence in the United States of a parallel 'Christian' (by which we actually mean Evangelical) media, watched by people who mostly do not watch mainstream media and never watched by anyone outside the target demographic. It's easy to see how the existence of such a thing - and for such a long time as well - could have a 'pillarising' and polarising effect. This is a significant contrast with broadcasting culture in most European and other 'Western' countries where the tendency has traditionally been to try to cover all bases, particularly from the various large public broadcasters.* It might also explain some the odd tendency in so much of mainstream American cultural output to conflate organised Christianity as anything other than a basically alien antagonist with Catholicism.
*Except, of course, for 'pillarised' societies in the post-war and Cold War decades - Italy, the Netherlands and so on.
I'm not quite sold on this thesis in this context. When I see the word "pillarization" I think of a society all of whose cultural institutions exist in parallel. In America, this is partly true. I would say that the separation is most complete in literature. The most financially lucrative Christian cultural industry is music. It's telling that these two are relatively inexpensive to produce. There's also significant crossover between the Christian music industry and the mainstream music industry; everyone likes to talk about how Katy Perry used to be a Christian singer, but the actually significant moment here was Amy Grant crossing over from Christian pop to regular pop in the early '90s. It's not all that uncommon now for an act to straddle that line.
What this thread is about is scripted fictional programming. There is a market for explicitly Christian movies (God's Not Dead and Heaven Is for Real both made a lot of money on a small budget), but in spite of that, not a lot of movies like that get made. My guess would be that it's difficult to find capital to make that sort of movie, despite the enormous returns that are possible. (A more pronounced version of this is why Mormon film is a practically nonexistent genre.) What's more common is the sort of movie that's not explicitly Christian but is nonetheless marketed in a way where it's understood to be primarily for that market. A good example of this is the Kurt Warner movie that just came out.
To get to what this thread is explicitly about, which is television, the notion of pillarization doesn't seem quite right to me because Christian television doesn't really exist. Christian television channels that cater to the Evangelical Protestant market generally do not produce scripted fictional programming, presumably as a matter of cost. What strikes me is that there aren't even TV shows that cater to a Christian audience in the way that movies do. (That, I guess, is why this thread was created). When I was young there were two long-running and successful shows that I can recall with religious themes on network TV: Touched by an Angel and 7th Heaven. Now, as far as I know, there are none, and it does not appear that anything has replaced them.