Sci-Fi has made mistakes in the past with originals and conversions, but in line with what Ian said, they no longer feel the need to try because trying and failing with a scripted show is expensive, but reality shows are cheap and almost guaranteed to attract a large enough audience to offset its marginal cost.
Though I agree with Ian on that, I do think that people do act like they do on reality shows in real life. They film these people twenty-four seven and then take 22mins or 44mins of film to make a show. For the other 10,058 or 10,036mins in the week, they're just like everyone else, and then the producers put them in situations that make good TV. Speaking of situations, I've never watched the Jersey Shore (because I live in NJ and think shows like this give us a bad (ok... worse) name and I refuse to support them) but from what I've seen on commercials and clips on CNN, what happens to them is typical of what does happen at the Jersey Shore; people get drunk, stupid, and violent. Yes, I am sure that people get on these shows and 'act' the entire time, but even then, they're characters are based on themselves or other people (if I wasn't lazy, I would find examples of both of these things taking place on Real World, and another show that I can't remember but could probably find on Google).
I've seen (and I can only imagine the perceived politeness of Canadians as the reason you have not...) women display exactly the same amount or even more catiness and/or bitchiness that the women on reality shows display. That stuff I always see as authentic, because let's face it, women are crazy. They can be great, but there's always that little bit of craziness waiting to pop out, and some women don't bother ever holding that back... lol
I do also agree with Ian's point on reality shows causing fame to be the aspirations of our children. When someone mentioned MegaMind in the new movies thread, I mentioned how I hoped that movie would be a message to kids that being smart was still something worthwhile. Not to get political, but with money being cut from the Art and Music departments at school, and the influx of reality TV, our children are stuck between conformity and fame, and I can hardly blame them for choosing fame. Creativity and intelligence need to be rewarded and seen as goals rather than what being successful with either attribute can bring.