Mark Jacobs stated that unlike some other big titles, Camelot Unchained will be financially successful with fewer paid subscribers. "We don't need one million subs to make money," he said. "If we get 50K paying subscribers a month it will justify the $5 million development budget." Of course, he admitted that they'd certainly be happy with more.
Jacobs also touched on other topics, including crafting and the absence of PvE. Players who want to both fight and craft extensively will need to rely on alts. as fighters will have limited crafting options. And don't think the world will be empty just because there will be no traditional PvE; Jacobs assured that there will be NPCs, noting "You can skin them, get materials off them, salvage their weapons, armor, etc. but you cannot level your RvR skills by doing that."
[Thanks to Mikkel for the tip!]