I play in a different fan-created server of an OLD online game, and they acquired the rights from the original owner, and got everything together enough to get listed on Steam. I honestly don't know if it was worth the effort.
Yes, there was a FLOOD of new players. Hundreds, maybe even a thousand or more, new accounts created in the few months since steam launch. The vast majority had one quick look around and were never seen again. A tiny handful, maybe 20-ish, have actually stuck around for more than a month. Easily three or four times that number were simply trolls, that only logged in to harass other players and spew vulgarity.