Maybe the presentation is important. Bruce Baugh on the rpgnet thread reckons that there's not enough support for Traveller "as gaming" - that there's "nothing about any of what any of it means in play".
Certainly the GDW CT material seemed to lack any kind of advice as to what to do with the games. (I dunno about T20. I'll remind myself next week when I get my book back

)
Another thing is the character generation. Namely, you're generally expected to play people who have retired or left whatever forces they're in. So... what are you supposed to do if you want to run say a campaign set while everyone is still kinda youthful and in the relevant service? While still in the Marines? Or the Army? Or still serving in the Scouts? There is bugger all support for that sort of thing in Traveller (First In, WBH, and Ground Forces notwithstanding). Or even not in a service at all? How about a cop campaign set on a single planet? Or if the PCs are in the Imperial Secret Service, hunting down fugitives across the sectors? Nope, that's never even been
mentioned AFAIK.
Instead as far as I can recall the only options we get in Traveller are "well, you're all between about 35 and 60, you're all retired (I think in CT you HAVE to be retired - there is no way to drop out willingly), and you're all either traders flying a rustbucket ekeing out a living, or your mercs doing missions for pay".
I don't think anyone nowadays could find the latter remotely inspiring. I think one thing that could attract people is a move away from the trading stuff. Nobody nowadays wants to do accounting in a roleplaying game.
But again, I have to sigh here. The one version of Traveller where people could play characters that were different (and actually could make a different to the setting) was TNE. And I dare say that's another reason why the old guard hated it.
Check the last line of my post. I'm not disagreeing. Just pointing out that as it stands, Traveller is still more popular than a LOT of games out there. I don't want the impression coming across to those who aren't playing that Traveller is just this old game no one plays anymore.
Well, sure. I'm not denying that it's popular. (y'know, it'd be nice to know what the "State of the Nation" is regarding Traveller. Loren was always tightlipped about how much each version was selling. Your reply is the first inkling I've had that Traveller is actually "more popular", though I don't know whether you mean in terms of current sales or in terms of people who have already bought a version of it).
I'm also not denying that it's still played. The problem is that
new people aren't coming along and starting to play the game. One might wonder why that would be important if the game is so popular, but we NEED new people because we always need new approaches and ideas (and more sales, of course

).
QLI is doing great work trying to attract people using the most popular system around and to keeping the momentum going with the TAs. But I really think Traveller needs to be able to reach new people, either by breaking their misconceptions or by changing itself to be more appealing.
One interesting possibility might be to go down WW's route. They had their huge sprawling, multigame World of Darkness, and they just ended it all. What they're doing now is a complete reboot. Same lines, but with a different background. They totally swept away the old setting (but they gave lots of warning and let it all go out with a bang) and started again.
God knows the OTU could to with a reboot. Sweep away all the inconsistencies, make the presentation more attractive, throw in LOTS of different campaign and gameplay options, make it more meaningful to the modern gamer, rebuild everything from the ground up so that it is
consistent and
sensible. Maybe that could make a difference.