I haven't got much faith in Gameforge either, but it really wouldn't require much of their resources to open a 2nd server with some old classic Tera code they have lying around.
If Gameforge and people like you use that temporary "classic" server (which wasn't even truly Classic) as an excuse for why a true, permanent classic wouldn't work or wouldn't be popular, then Gameforge and people like you are just lying to themselves.
Classic fans like me and many others saw that advertisement for the temporary server, saw how it wasn't even a true Classic patch, and then immediately passed on it. Why would we even bother trying it out if it's only temporary?
Stop using that dumb argument already. That "classic" attempt was unappealing garbage and shouldn't be compared to a real classic attempt.