After a seven-year hiatus of a Star Trek movie and the success with Trek XI, I think it is possible that Star Trek will live forever in some fashion. Oh sure, there were thoughts back when TNG first aired that probably didn't think TNG would last more then a season or two. I'm also sure that back in the 60's the original cast probably thought Trek was over in 69' when TOS was cancelled. But alas, 40 years later and Star Trek is bigger then ever! I think the film has even revamped TrekBBS. There has been more positive talk about Trek in these forums since long I can remember. Think Star Trek will live forever?
Life, Jim... But not as we know it. Star Trek has embedded itself in the American psyche pretty deeply - easily as deeply as "Flash Gordon" or "Buck Rogers." And that concept - "Don't give me that Buck Rogers shait..." continues today despite, not because of, that Twiki thing from the eighties. Forever? Probably not. But we have an easy fifty years left, and probably more. We've left a deep footprint, and time won't wash it clean easily.
Ask me again in 40 years when Zac Quinto is playing Old Spock on Star Trek 145 (or whatever number it'll be) in the first movie with the third cast to play Kirk, Spock, etc.....
This is why I thought it was so clever that Roger Ebert gave his review of the movie the headline "The Franchise on the Edge of Forever". I really thought it was over after "Star Trek: Nemesis" and "These Are The Voyages...". This whole re-boot idea has increased the potential life span of the franchise exponentially. Not sure if it'll be another James Bond, but there's a possibility now.
If done right we could get another 10 years of peakness but once again no matter how succesful your reboot is you will land in MILKING terrority eventually and just fall off that cliff.
It'd be kind of cool if it was lost for a few hundred years and then dug up and declared the one true answer to all questions related to God, time and the universe.
Probably, though we won't be around to see it. As long as there are fans who are willing to part with their hard-earned quatloos to see Trek, it'll be around.
That's the main issues for writers as most of our technology has already almost surpass that of TOS. There will come a point where Trek will become purely a soap opera.
The Scene; 2550, some broke down space station in the middle of nowhere. Some old Voyager episode is playing. "Bwaaaahahaha! That's You!" "Shut up..." "They said he's a Talaxian - that's you!" "Shut up, you plik - I don't look like that..." "Your wife wishes you looked that good... Talaxian... Bwaaahaha!.." "I'm gonna frackin punch you. Stupid program..."
The jury is out on whether the human race will last that long, let alone our civilisation, let alone a TV show.
Maybe archeologists from a distant civilisation will find fossils of the recordings of the show and interpret it as a log of our everyday life!