Not to mention that BSG and SG have lower production values than Star Trek
BSG managed to squeeze a lot out of their budget and look okay but that's another problem - a
Star Trek TV series cannot look just "okay" without impinging on the movie brand, which has got to remain at a premium level in order to compete in the summer blockbuster frenzy, where looks are everything nowadays (and even moreso in the wake of
Avatar.)
It would be tempting to say, "hey, we'll take
Star Trek that only looks as good as
BSG!" Personally, I'd take that -
BSG didn't look so bad. But that's not how corporations think. If
Star Trek is a "premium brand," it must be kept at a higher level than
BSG. If that means movies only, no TV, that's okay. The movie revenues might matter so much more than TV that nothing is worth risking the movie revenues over.
The other complication is Paramount owning the movie rights vs Viacom owning TV. That's an awkward situation. It's hard to get two separate corporations to cooperate on anything. Their default instinct is to not cooperate and to spend their money and time on other opportunities.
I still think the main problem is corporate inertia. CBS could make money off
Star Trek on TV, but who is going to champion it? It's a brand partly owned by another corporation. CBS is not sci-fi friendly. Championing
Star Trek would not be a good career move for anyone at CBS and the only things that happen at corporations are the things that are good career moves for somebody.