1. ABC/Disney and Marvel have achieved full penetration of SF fan culture. I'm conflicted. Back in the 20th Century, fan culture was a ghetto. It was the ultimate, genuine counterculture - because it was considered "loser" culture by so many. That meant a lot of negatives, of course, but it did allow some positives to flourish: a defiance of conformity; an interest in the truly original, which is often less comfortable and attractive than what the mainstream thinks is original; a love of ideas, even when their presentation was clunky and awkward (think '70s sci fi movies...so much spandex!)
Today's fan culture is mainstream culture. It is fully engulfed, er, embraced by "cool kids," movie producers and corporate marketing executives. To some old-time fans, this is vindication: At last everyone else finally understands what we've known from the beginning! This stuff is legit and it's cool! But being embraced by the cool is like being turned by a vampire: Sure, you get immortality and broody good looks and really great lighting (at least, if you're a CW vampire). But you are different from what you were...and worse, you are under the influence of the vampire that turned you.
Go to a convention. Half of them are now "media" conventions - not only are they not about science fiction, you'll be hard-pressed to find attendees who read books for fun. You'll find costumers (excuse me, cosplayers) who are more interested in showing off their hot bodies than in the costumes themselves - the "sexy kitten Halloween costume" effect. (Not that I have anything against hot bodies, mind you. In fact- okay, let's let that critique slide. I am a visual creature. Sigh.) Their discourse isn't controlled by media corporations, but it's certainly shaped by them. Now corporations set the fan agenda, not the other way around.
2. But marketing can only go so far. Marketing is a craft, not a science. The best campaign in the world can fail without a good product behind it. I have to admit, I'm always going to hope for and expect the best from Joss Whedon. He isn't a demigod, but he's smart and funny and one of the few cinema storytellers out there who seems willing to push hard for something good. Even his failures are usually interesting. That said, the AoS pilot wasn't mind-blowing; I'm hoping that it gets better.