Here's the thing. I am currently going through and mainlining Babylon 5 into my brain, for a secret writerly reason of which I cannot speak at this moment. (Because it is secret. And writerly.) I never watched the show when it was on, for a wide variety of reasons including the fact that I am very apathetic about popular culture as a whole: My general philosophy is that if it's still fondly remembered by the time I get around to watching it two decades after the fact, it's probably very good and well worth waiting for. If it drops completely off the radar and everyone scorns it for being a failure that started off promising and proceeded to head downhill like a rocket-powered toboggan, it's probably 'Heroes'. (But I kid the series!) Seriously, if it's not worth watching, I probably will find out about it in the decade or so before I get around to it. It's the Planetary philosophy: "We're archaeologists. We'll dig you up and work it all out in a couple of years."
(The best part of this philosophy is that by the time I get around to watching it, the DVDs are cheap and I don't have to wait through the offseasons.)
So the point is, I have a lot of thoughts about Babylon 5, many of which I am restraining myself from saying due to writerly secret reasons. But one thing I do keep thinking about, and am allowing myself to talk about even though I'm shutting up about a lot of it, is, "Why did the series never come back?" I have heard from my lovely and intelligent wife that JMS, creator/producer of the series, doesn't really have an interest in doing more on account of how hard it was to get the first series made, and how many of the actors have unfortunately passed on, and how he's more or less told the story he wanted to tell. And while those strike me as true (because I know my wife and in addition to being lovely and intelligent, she knows metric tons about 'Babylon 5'), they also strike me as good things to tell yourself, if you're a former producer of a science-fiction series with a small-but-devoted fanbase that can't get renewed. It does seem to me that there has to be at least an element of falsehood there...because 'Crusade'. Clearly, JMS at one point felt like there were enough ideas floating around in the B5 universe to sustain a second five-year series. That series was canceled with four years of stories left untold. That suggests to me that there are more stories he at least was willing to try to tell.
The question is, "Why can't he?" Because let's face it, we live in a very different era than we did in 1999 (when the series was canceled.) Shows with cult followings and long tails now routinely make returns, from 'Family Guy' to 'Doctor Who' to 'Futurama' to 'Serenity' (which itself is probably due for another return a few years from now. Big Red Button, guys!) We live in an archival culture now, where quality television is not dependent on the vagaries of an inconsistent syndication schedule to gain a following among science-fiction fans. So why is it that Babylon 5 nostalgia isn't leading us back towards a revival of the series and an explanation of the Drakh war? At the very least, Dark Horse should be putting out a comic book of this stuff.
I think the answer is that the very thing that Babylon 5 fans loved has given the series a reputation that prevents it from gaining that kind of return following. Everyone talked, during the period the series was on the air, about its intricate continuity and long-running storyarcs. About hints that began in the pilot and slowly unfolded over the course of five whole seasons. (I used to have a button that said on it, "Doctor Who explained, Babylon 5 predicted, Star Trek...apologized for." It's funny if you're an obsessive Doctor Who geek.) The problem with this is that it intimidates people away from the show. Even in an archival era, where the series is ten bucks a season and you can get through the whole thing in a couple of months if you work at it, Babylon 5 is legendary for requiring an investment to get through. (And it's also got an entirely undeserved reputation as having a long slog of dull episodes to get through before you hit the "good stuff", by which fans tend to mean the metastory-heavy shows. Personally, I think that Season One's standalone episodes are plenty good...but I'd never have known that if I'd listened to the people telling me to watch the show.)
The long and short of it is, we are now in an era where practically every series takes its model from B5, and sci-fi fans should not be scared away from a series with storyarcs. But because it was so innovative at the time, and because so many people talk about nothing but the arc plots, I think people somehow assume they're going to be harder to follow or require more attentive viewing than any other series, and they don't know if they want to put in the effort. Which prevents the show from developing the kind of following that sells DVDs, comics, merchandising, and other stuff that would make the bean-counters in Hollywood stand up, take notice, and shove a dump truck full of money in Straczynski's face and say, "Is this enough to make the kind of show you want?" Which is probably what it would take to overcome his reluctance to dive back into it all.
Basically, what I think I'm saying is, "If you've been waiting 20 years to watch 'Babylon 5' because you were worried about having to mainline the whole thing into your brain over the course of a month or so, you don't need to be. I'm not doing that because it's the only way to watch the show. I'm doing it for secret reasons. Shhhhhh."