SoR, I think, will do more than just 'survive'. It may not approch EQ proportions, however, EQ appeals to a (generalization) different type of player. In EQ, it's all about be 133t and getting all that ph4t 13wt. Ryzom is more community and civilization building, as well as the story-line.
There is also an even greater storyline that I think hasn't been picked up yet.. this is only Chapter 1: Atys. That would lead one to believe that there will be other chapters and worlds as well, those evil Karavan invading and enslaving other planets.
There will, of course, need to be more content added for continued playability. Look at EQ. It stated not even a quarter as 'big' as it is now, and it's player-base in the beginning was really small as well. But, it kept chugging, even with all of it's original bugs and issues and is still trying to work out bugs and balance.
Also remember, that once the base work is done, it's fairly cheap to run a server. All you need is electricity, the ISP, and a tech to reboot/restore if things really mess up. Most of us, however, dont' have a clue as to the size of the other communities. I forgot how to read French years ago, so can't tell if they are empty, full, or what, and since we can't log into those serves and see for ourselves, unless someone comes and says it's empty, I'd like to assume it's thriving.
Something else to remember is that it did have European designers, not American, and they know what they like better than we do. The NA server itself, as well as service for us, may just be because it's such a large market (we seem to have a lot of "disposable income"), and one more server as stated above really doesn't take that much to maintain, that's it's well worth it.
All in all, I'd not worry too much about SoR going away, it'll probably actually grow if everyone goes out and uses the invite a friend opportunity, then the other games come out and people see it's just more of the same thing with slightly different graphics, while SoR offers something different and new.
