I agree. It's not that I don't see $50 worth of value; it's that I can too easily imagine a substantial fraction of their market opting not to pay. Even at $30 I think they'd get a whole lot more action (and they could still have done $5 a month to try to encourage annual subscriptions).
I think the bigger problem has to do with other aspects of the model, though. (Link below for convenience.) The lack of content for non-subscribers sufficient to attract new customers seems like an dangerous maneuver.
Providing even just non-advanced search functionality and a tracker (with no stats) would keep so many people coming, many of whom—given the right pushes in contextually-relevant moments and interfaces—would surely do better for them.