The vast vast vast vast majority of people watch tv through network television and cable. We may be slowly heading towards a day where streaming tv overtakes the standard way of watching, especially as technology gets better, and things like the new chromecast become more prevelant, but we are no where close to that being the norm right now. I think a lot of younger people's perceptions are skewed because they can honestly say things like "most of my friends don't even have cable" or "I dont know anyone who channel surfs anymore" because for them its true. But that's because people tend to associate with people like themselves, so their experiences seem the norm, but we're still a ways away. Approximately 25 million people watched the NFL premiere on Thursday night, streaming audiences are nothing close to that right now, they just aren't.
Getting B5 on Netflix would be a GREAT thing, but getting back on tv is equally, if not more important right now if you want to drum up interest.