The size of the fanbase is not the issue. Franchises aren't revived based on their fan base, if that was healthy then they wouldn't have died in the first place. It's brand recognition that matters, and I think more people, of this generation especially, have at least heard of Stargate. Probably more so than many of the other franchises that get a reboot in fact.
Bingo. There's nothing stopping
Stargate or
Star Trek from returning to TV, except that the folks in charge probably have other projects taking up their time that seem to them to be easier routes to making money. The fact that space opera has died on TV has got to be a huge disincentive to attempting that particular format. Which is not the same as saying space opera can't be made to work, just that there are business and institutional barriers to anyone trying.
And what worked for TOS or TNG is completely irrelevant now. Neither show would survive on broadcast if launched now, because the TV business has changed.
I think Trek (until JJ) just didn't move with the times. A modern mainstream audience just isn't going to accept men with American accents and rubber faces pretending to be aliens. Either the franchise has to settle for less and become a Syfy level show, or modernize and lose some of the corny stuff - but it did neither.
One day,
Star Trek will be back on TV (with a well known movie franchise keeping the brand name buoyant right now, that's more likely than the return of
Stargate, which I wouldn't rule out either) and when it returns - on cable, because it won't survive on broadcast anymore - it's going to have to reinvent itself even more than JJ Abrams did for the movies.
If it's on SyFy (please God no), it will be like
Stargate. If it's on TNT, it will be the most like traditional
Trek we could expect to see - more like DS9 than any of the others. If it's on FX, it will be more brutal, complicated and sexy than we're used to. If it's on AMC, it will brutal, complicated, sexy and maybe a bit smarter and arty than FX's version. If it's on HBO or Showtime, it will take all those elements and amp them up even more. If it's on Starz, it will be like HBO or Showtime, but more graphically sexy and violent and also stupider and more crass. If it's on The Cartoon Network, it will be animated of course, and a lot like
The Clone Wars. If it's on the CW, it will be about angsty teenage space cadet vampires and we'll all want to slit our wrists.
So as long as it doesn't end up on SyFy or the CW,
Star Trek on TV could be very interesting and leave the franchise to date in the dust. And the fights that break out around here will make all the squawking about Abrams'
Trek look like a playground scuffle. Personally, I can't wait.