The available audience for live eyes watching has drastically changed from when B5 and Farscape were on.
Which probably means that the networks are going to have to adapt to compete with providers like Netflix if they plan to survive. I don't get the feeling that even the networks still think "live eys watching" is the standard of the future. [EDIT: BSG's so-called "failure" is a case in point: what it proved was that the traditional ratings system is dead
, not that space opera is dead.]
Yes, some SciFi/Fantasy can get big ratings these days, but, it's typically down to Earth, no major Space opera plots or lots of aliens.
And yet ironically, it's cheaper than ever to do space opera plots and aliens.