Plus, career tv writers are more familiar with the genre, largely because of Star Trek.
I don't think they're really very familiar with the science fiction genre, I think that they're just familiar with ST, which, though it IS science fiction, is much more limited in scope than science fiction as a whole. Which is why I think in recent years the franchise has shown a certain poverty of mindbendingly new ideas.
And who says Bermaga wouldn't welcome an established sci-fi author? I think most high-profile writers would see writing for TV as a step down. A few years back they got a couple well-known authors to write X-Files episodes, and it was a huge deal.
Probably Bermaga WOULD welcome a high profile sci-fi author, if he dropped into their laps and begged for work at union scale. But high profile writers tend not to do that, they must be courted, and landing one of them is a coup (hence the publicity at X-Files). I don't know who X-Files hired (and I'm curious, could you tell me?), but I'd guess the producers made a special effort to reach out to those authors. I'm not really certain about the early history of ST (and if I'm wrong, please correct me) but I imagine that Frederic Brown, Norman Spinrad, Thedore Sturgeon and others may not have rushed to dump their wares into Roddenberry's lap when he started his new, untested show - he probably had to ask some of them to contribute, and maybe had to even pay them a little more than usual.
I think that Bermaga really ought to try to make a similar effort. They don't even have to go after the stars of the SF world. As I said before, there are many talented sf writers who, though they do not write best sellers, do sell steadily and write well. Most writers, even moderately successful ones, do not make a great deal of money for novels (especially when the fees are spread out over the time it takes to write them) and would probably be happy to write an episode if offered a good (though not exorbitant) fee. I can't imagine that ALL SF authors despise ST as trash. In fact, I'd be willing to bet some are closet trekkies who'd love to do it (the Whoopi Goldberg syndrome).
I think however, that Bermaga are simply not willing to put up with the hassle of working with someone who is not thouroughly familiar with writing for television and kowtowing to the producers, and probably prefer to put their effort and money toward, um, CGI effects, architectural catsuits and industrial-strength underwired bras, I guess. X-Files showed that SF authors COULD be hired, but for whatever reason Bermaga are not choosing to do it.