I don't think you'll ever get the true cerebral experience that you used to get with some shows.
It's all very much focused on adventure of the week romps that can be produced easily fairly easily and appeal to a wide audience due to their family drama angle. (Warehouse 13, Eureka, Terra Nova, Falling Skies). Granted not all of these have been successful.
Cerebral shows like TNG, DS9 and Voyager won't ever be coming back, at least not on mainstream tv. Their time has been and gone.
Ever since Lost premiered and showed that character based drama can hook sci fi /fantasy audiences the networks have continued to lean in that direction. It was more of a drama than sci fi and as we all should know Drama is a genre that brings in mega viewing figures on tv.
Until a person/people come along with a solid model from which to digitally distribute a sci fi show which i actually profitable than i don't think we'll be seeing any deep and serious shows anytime soon.
Personally i think TV as we know it will change within the next decade as digital content and distribution becomes more mainstream which in turn will render terrestrial broadcasts obsolete in some way.
TV is a business at the end of the day and the money is all that matters in the end. I don't think Sci Fi has died as a genre but it has changed and adapted with the times as has every genre out there.